Oxides for new-generation electronics

Ferromagnetic metallic Sr-rich Ln1/2 A1/2 CoO3 cobaltites with spontaneous spin rotation

Written on 11 January 2022.

Título : Ferromagnetic metallic Sr-rich Ln_1/2 A_1/2 CoO₃ cobaltites with spontaneous spin rotation

Autores: Jessica Padilla-Pantoja, Arnau Romaguera, Xiaodong Zhang, Javier Herrero-Martín, Francois Fauth, Javier Blasco, and José Luis García-Muñoz,*

Citation and DOI:

Phys. Rev. B 104, 054411 – Published 9 August 2021
DOI: https://doi.org/10.1103/PhysRevB.104.054411

PlumX: Ferromagnetic metallic Sr-rich Ln1/2 A1/2 CoO 3 cobaltites with spontaneous spin rotation

The Pr_0.50Sr_0.50CoO₃ perovskite exhibits unique magnetostructural properties among the rest of ferromagnetic (FM)/metallic Ln_0.50Sr_0.50CoO₃ compounds. The sudden orthorhombic-tetragonal (Imma → I4/mcm) structural transition produces an unusual magnetic behavior vs temperature and external magnetic fields. The symmetry change is responsible for a spontaneous spin rotation in this metallic oxide.

Hits: 169

Bulk photovoltaic effect in hexagonal LuMnO3 single crystals

Written on 31 December 2021.

Título : Bulk photovoltaic effect in hexagonal

{LuMnO}_{3}

single crystals

Autores: Yunwei Sheng, Ignasi Fina, Marin Gospodinov, Aaron M. Schankler, Andrew M. Rappe, and Josep Fontcuberta.

Citation and DOI:

Phys. Rev. B 104, 184116
DOI: 10.1103/PhysRevB.104.184116

PlumX: Bulk photovoltaic effect in hexagonal LuMnO3 single crystals

When illuminating a non-centrosymmetric material with light of energy higher than the bandgap, a net current appears because the electrons do not see the same electronic environment in one direction and the opposite direction, thus they hold a net momentum. This is the bulk photovoltaic effect (BPE), which depends on the light polarization.

Hits: 342

Efficient spin pumping into metallic SrVO3 epitaxial films

Written on 21 December 2021.

Título : Efficient spin pumping into metallic SrVO₃ epitaxial films

Autores: Francesc Macià, Mathieu Mirjolet, Josep Fontcuberta

Citation and DOI: Journal of Magnetism and Magnetic Materials 546, 15 March 2022, 168871
DOI: 10.1016/j.jmmm.2021.168871

PlumX: Efficient spin pumping into metallic SrVO3 epitaxial films

Spin-charge conversion requires materials with a large spin-orbit coupling, which is typically obtained in heavy metal (Pt, etc.) ions. Here we demonstrate spin pumping across interfaces between metallic SrVO₃, where V is a 3d1 ion, epitaxial thin films and ferromagnetic Ni₈₀Fe₂₀.

Hits: 299

Direct and Converse Flexoelectricity in Two-Dimensional Materials

Written on 10 December 2021.

Título : Direct and Converse Flexoelectricity in Two-Dimensional Materials

Autores: Matteo Springolo, Miquel Royo, and Massimiliano Stengel

Citation and DOI: Physical Review Letters, Vol. 127, Iss. 21 — 19 November 2021
DOI: https://doi.org/10.1103/PhysRevLett.127.216801

PlumX: Direct and Converse Flexoelectricity in Two-Dimensional Materials

Building on recent developments in electronic-structure methods, we define and calculate the flexoelectric response of two-dimensional (2D) materials fully from first principles. In particular, we show that the open-circuit voltage response to a flexural deformation is a fundamental linear-response property of the crystal that can be calculated within the primitive unit cell of the flat configuration.

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Determination of the Crystal Structures in the A-Site-Ordered YBaMn2O6 Perovskite

Written on 03 December 2021.

Título : Determination of the Crystal Structures in the A-Site-Ordered YBaMn₂O₆ Perovskite

Autores: Javier Blasco*, Gloria Subías, José Luis García-Muñoz, François Fauth, and Joaquín García

Citation and DOI:

J. Phys. Chem. C 2021, 125, 35, 19467–19480

Publication Date:August 30, 2021

DOI: https://doi.org/10.1021/acs.jpcc.1c04697

PlumX: Determination of the Crystal Structures in the A-Site-Ordered YBaMn2O6 Perovskite

We present a complete structural study of the successive phase transitions observed in the YBaMn₂O₆ compound with the layered ordering of cations on the perovskite A-site. We have combined synchrotron radiation X-ray powder diffraction and symmetry-adapted mode analysis to describe the distorted structures as pseudosymmetric with respect to the parent tetragonal structure.

Hits: 335

High-Temperature Synthesis and Dielectric Properties of LaTaON2

Written on 30 November 2021.

Título : High-Temperature Synthesis and Dielectric Properties of LaTaON₂

Autores: Augustin Castets, Ignasi Fina, Jhonatan R. Guarín, Judith Oró-Solé, Carlos Frontera, Clemens Ritter, Josep Fontcuberta*, and Amparo Fuertes*

Citation and DOI:

Inorg. Chem. 2021, 60, 21, 16484–16491

Publication Date:October 8, 2021

DOI: 10.1021/acs.inorgchem.1c02325

PlumX: High-Temperature Synthesis and Dielectric Properties of LaTaON2

The development of new synthetic methodologies of perovskite oxynitrides is challenging but necessary for the search of new compounds and the investigation of new properties. Here, we report a new method of preparation of the perovskite LaTaON₂ that has been investigated as a pigment and photocatalyst for water splitting.

Hits: 363

Exact Long-Range Dielectric Screening and Interatomic Force Constants in Quasi-Two-Dimensional Crystals

Written on 26 November 2021.

Título : Exact Long-Range Dielectric Screening and Interatomic Force Constants in Quasi-Two-Dimensional Crystals

Autores: Miquel Royo and Massimiliano Stengel

Citation and DOI:

Phys. Rev. X 11, 041027 – Published 8 November 2021
DOI: https://doi.org/10.1103/PhysRevX.11.041027

PlumX: Exact Long-Range Dielectric Screening and Interatomic Force Constants in Quasi-Two-Dimensional Crystals

Electrons in insulating crystals polarize in response to an externally applied electric field, resulting in a partial suppression of the field amplitude; such a phenomenon is known as “dielectric screening.” While much effort has gone into developing a quantitative understanding of this behavior and its impact on materials properties, 2D crystals remain challenging to describe by means of established modeling strategies.

Hits: 360

Strong strain gradients and phase coexistence at the metal-insulator transition in VO2 epitaxial films

Written on 23 November 2021.

Título : Strong strain gradients and phase coexistence at the metal-insulator transition in VO₂ epitaxial films

Autores: Laura Rodríguez, Felip Sandiumenge, Carles Frontera, José Manuel Caicedo, Jessica Padilla, Gustau Catalán, José Santiso

Citation and DOI: Acta Materialia, Volume 220, 2021, 117336, ISSN 1359-6454,
DOI: https://doi.org/10.1016/j.actamat.2021.117336

PlumX: Strong strain gradients and phase coexistence at the metal-insulator transition in VO2 epitaxial films

The proximity of a thermodynamic triple point and the formation of transient metastable phases may result in complex phase and microstructural trajectories across the metal-insulator transition in strained VO₂ films. A detailed analysis using in-situ synchrotron X-ray diffraction unveils subtle fingerprints of this complexity in the structure of epitaxial films. During phase transition the low-temperature monoclinic M1 phase is constrained along the {111}_R planes by the coexisting high-temperature R phase domains, which remain epitaxially clamped to the substrate.

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Positive Effect of Parasitic Monoclinic Phase of Hf0.5Zr0.5O2 on Ferroelectric Endurance

Written on 16 November 2021.

Título : Positive Effect of Parasitic Monoclinic Phase of Hf_0.5Zr_0.5O₂ on Ferroelectric Endurance

Autores: Tingfeng Song, Saúl Estandía, Huan Tan, Nico Dix, Jaume Gàzquez, Ignasi Fina, Florencio Sánchez,

Citation and DOI: Adv. Electron. Mater. 2021, 2100420.
DOI: https://doi.org/10.1002/aelm.202100420

PlumX: Positive Effect of Parasitic Monoclinic Phase of Hf0.5Zr0.5O2 on Ferroelectric Endurance

Endurance of ferroelectric HfO₂ needs to be enhanced for its use in commercial memories. This work investigates fatigue in epitaxial Hf_0.5Zr_0.5O₂ (HZO) instead of polycrystalline samples. Using different substrates, the relative amount of orthorhombic (ferroelectric) and monoclinic (paraelectric) phases is controlled. Epitaxial HZO films almost free of parasitic monoclinic phase suffer severe fatigue. In contrast, fatigue is mitigated in films with a greater amount of paraelectric phase.

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Determination of the Crystal Structures in the A-Site-Ordered YBaMn2O6 Perovskite

Written on 12 November 2021.

Título : Determination of the Crystal Structures in the A-Site-Ordered YBaMn₂O₆ Perovskite

Autores: Javier Blasco*, Gloria Subías, José Luis García-Muñoz, François Fauth, and Joaquín García

Citation and DOI:

J. Phys. Chem. C 2021, 125, 35, 19467–19480

Publication Date:August 30, 2021

DOI: https://doi.org/10.1021/acs.jpcc.1c04697

PlumX: Determination of the Crystal Structures in the A-Site-Ordered YBaMn2O6 Perovskite

We present a complete structural study of the successive phase transitions observed in the YBaMn₂O₆ compound with the layered ordering of cations on the perovskite A-site. We have combined synchrotron radiation X-ray powder diffraction and symmetry-adapted mode analysis to describe the distorted structures as pseudosymmetric with respect to the parent tetragonal structure. The YBaMn₂O₆ compound shows three consecutive phase transitions on cooling from 603 K down to 100 K. It undergoes a first-order structural transition at T₁ ≈ 512 K from a C2/m cell with a single Mn site to a P2₁/c cell with two nonequivalent Mn sites.

Hits: 330

Orbital occupancy and hybridization in strained SrV O 3 epitaxial films

Written on 05 November 2021.

Título : Orbital occupancy and hybridization in strained

SrV O_{3}

epitaxial films

Autores: Mathieu Mirjolet,*, Hari Babu Vasili, Adrian Valadkhani, José Santiso, Vladislav Borisov, Pierluigi Gargiani, Manuel Valvidares, Roser Valentí, and Josep Fontcuberta

Citation and DOI:

Phys. Rev. Materials 5, 095002 – Published 9 September 2021
DOI: https://doi.org/10.1103/PhysRevMaterials.5.095002

PlumX: Orbital occupancy and hybridization in strained SrVO3 epitaxial films

Oxygen packaging in transition metal oxides determines the metal-oxygen hybridization and electronic occupation at metal orbitals. Strontium vanadate

(SrV O_{3})

, having a single electron in a

3 d

orbital, is thought to be the simplest example of strongly correlated metallic oxides. Here, we determine the effects of epitaxial strain on the electronic properties of

SrV O_{3}

thin films, where the metal-oxide sublattice is corner connected.

Hits: 354

Effect of Humidity on the Writing Speed and Domain Wall Dynamics of Ferroelectric Domains

Written on 02 November 2021.

Título : Effect of Humidity on the Writing Speed and Domain Wall Dynamics of Ferroelectric Domains

Autores: Irena Spasojevic, Albert Verdaguer, Gustau Catalan, Neus Domingo

Citation and DOI: Adv. Electron. Mater. 2021, 2100650.
DOI: https://doi.org/10.1002/aelm.202100650

PlumX: Effect of Humidity on the Writing Speed and Domain Wall Dynamics of Ferroelectric Domains

The switching dynamics of ferroelectric polarization under electric fields depends on the availability of screening charges in order to stabilize the switched polarization. In ferroelectrics, thin films with exposed surfaces investigated by piezoresponse force microscopy (PFM), the main source of external screening charges is the atmosphere and the water neck, and therefore relative humidity (RH) plays a major role.

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Common workflows for computing material properties using different quantum engines

Written on 19 October 2021.

Título : Common workflows for computing material properties using different quantum engines

Autores: Sebastiaan P. Huber, Emanuele Bosoni, Marnik Bercx, Jens Bröder, Augustin Degomme, Vladimir Dikan, Kristjan Eimre, Espen Flage-Larsen, Alberto Garcia, Luigi Genovese, Dominik Gresch, Conrad Johnston, Guido Petretto, Samuel Poncé, Gian-Marco Rignanese, Christopher J. Sewell, Berend Smit, Vasily Tseplyaev, Martin Uhrin, Daniel Wortmann, Aliaksandr V. Yakutovich, Austin Zadoks, Pezhman Zarabadi-Poor, Bonan Zhu, Nicola Marzari & Giovanni Pizzi

Citation and DOI:

npj Comput Mater 7, 136 (2021)
DOI: https://doi.org/10.1038/s41524-021-00594-6

PlumX: Common workflows for computing material properties using different quantum engines

The prediction of material properties based on density-functional theory has become routinely common, thanks, in part, to the steady increase in the number and robustness of available simulation packages. This plurality of codes and methods is both a boon and a burden. While providing great opportunities for cross-verification, these packages adopt different methods, algorithms, and paradigms, making it challenging to choose, master, and efficiently use them. We demonstrate how developing common interfaces for workflows that automatically compute material properties greatly simplifies interoperability and cross-verification.

Hits: 308

Polarization and Resistive Switching in Epitaxial 2 nm Hf0.5Zr0.5O2 Tunnel Junctions

Written on 01 October 2021.

Título : Polarization and Resistive Switching in Epitaxial 2 nm Hf_0.5Zr_0.5O₂ Tunnel Junctions

Autores: Milena Cervo Sulzbach, Huan Tan, Saúl Estandía, Jaume Gàzquez, Florencio Sánchez, Ignasi Fina*, and Josep Fontcuberta*

Citation and DOI:

ACS Appl. Electron. Mater. 2021, 3, 8, 3657–3666

Publication Date:August 12, 2021

DOI: https://doi.org/10.1021/acsaelm.1c00604

PlumX: Polarization and Resistive Switching in Epitaxial 2 nm Hf0.5Zr0.5O2 Tunnel Junctions

In the quest for reliable and power-efficient memristive devices, ferroelectric tunnel junctions are being investigated as potential candidates. Complementary metal oxide semiconductor-compatible ferroelectric hafnium oxides are at the forefront. However, in epitaxial tunnel devices with thicknesses around ≈4–6 nm, the relatively high tunnel energy barrier produces a large resistance that challenges their implementation. Here, we show that ferroelectric and electroresistive switching can be observed in ultrathin 2 nm epitaxial Hf_0.5Zr_0.5O₂ (HZO) tunnel junctions in large area capacitors (≈300 μm²).

Hits: 465

Switchable photovoltaic response in hexagonal LuMnO3 single crystals

Written on 21 September 2021.

Título : Switchable photovoltaic response in hexagonal LuMnO₃ single crystals

Autores: Yunwei Sheng, Ignasi Fina, Marin Gospodinov, and Josep Fontcuberta

Citation and DOI: Appl. Phys. Lett. 118, 232902 (2021)
DOI: https://doi.org/10.1063/5.0053379

PlumX: Switchable photovoltaic response in hexagonal LuMnO3 single crystals

Hexagonal manganites, such as h-LuMnO₃, are ferroelectric with its polar axis along the hexagonal axis and have a narrow electronic bandgap (≈1.5 eV). Using Pt electrodes, h-LuMnO₃ single crystals display a strong rectification, characteristic of a Schottky diode, and a large photoresponse. It is found that the short circuit photocurrent density J_sc along the polar axis is modulated (up to 25%) by the direction of the ferroelectric polarization P, leading to a short circuit photocurrent loop that mimics the ferroelectric polarization. However, a non-switchable J_sc persists. Diffusion photocurrent is shown to dominate current-in-plane measurements and contributes to the non-switchable J_sc.

Hits: 463

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

Written on 14 September 2021.

Título : Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO₃ Transparent Thin Films

Autores: Dong Han, Rahma Moalla, Ignasi Fina, Valentina M. Giordano, Marc d’Esperonnat, Claude Botella, Geneviève Grenet, Régis Debord, Stéphane Pailhès, Guillaume Saint-Girons, and Romain Bachelet*

Citation and DOI:

ACS Appl. Electron. Mater. 2021, 3, 8, 3461–3471 Publication Date:July 28, 2021

DOI: https://doi.org/10.1021/acsaelm.1c00425

PlumX: Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

The impact of epitaxial strain on the structural, electronic, and thermoelectric properties of p-type transparent Sr-doped LaCrO₃ thin films has been investigated. For this purpose, high-quality fully strained La_0.75Sr_0.25CrO₃ (LSCO) epitaxial thin films were grown by molecular beam epitaxy on three different (pseudo)cubic (001)-oriented perovskite oxide substrates: LaAlO₃, (LaAlO₃)_0.3(Sr₂AlTaO₆)_0.7, and DyScO₃. The lattice mismatch between the LSCO films and the substrates induces in-plane strain ranging from −2.06% (compressive) to +1.75% (tensile).

Hits: 465

Magnetocapacitance effect and magnetoelectric coupling in type-II multiferroic HoFeWO 6

Written on 10 September 2021.

Título : Magnetocapacitance effect and magnetoelectric coupling in type-II multiferroic

{HoFeWO}_{6}

Autores: Moein Adnani,*, Melissa Gooch, Liangzi Deng, Stefano Agrestini, Javier Herrero-Martin, Hung-Cheng Wu, Chung-Kai Chang, Taha Salavati-fard, Narayan Poudel, José Luis García-Muñoz, Samira Daneshmandi, Zheng Wu, Lars C. Grabow, Yen-Chung Lai, Hung-Duen Yang, Eric Pellegrin, and Ching-Wu Chu

Citation and DOI:

Phys. Rev. B 103, 094110 – Published 17 March 2021
DOI: https://doi.org/10.1103/PhysRevB.103.094110

PlumX: Magnetocapacitance effect and magnetoelectric coupling in type-II multiferroic HoFeWO6

We have investigated the multiferroicity and magnetoelectric (ME) coupling in

Ho Fe W O_{6}

. With a noncentrosymmetric polar structure (space group Pna

2_{1}

) at room temperature, this compound shows an onset of electric polarization with an antiferromagnetic ordering at the Néel temperature (

T_{N}

) of 17.8 K. The magnetic properties of the polycrystalline samples were studied by DC and AC magnetization and heat capacity measurements.

Hits: 458

Insights into the atomic structure of the interface of ferroelectric Hf0.5Zr0.5O2 grown epitaxially on La2/3Sr1/3MnO3

Written on 31 August 2021.

Título :

Insights into the atomic structure of the interface of ferroelectric Hf_0.5Zr_0.5O₂ grown epitaxially on La_2/3Sr_1/3MnO₃

Autores:

Saúl Estandía, Tengfei Cao, Rohan Mishra, Ignasi Fina, Florencio Sánchez, and Jaume Gazquez

Citation and DOI:

Phys. Rev. Materials 5, 074410 – Published 28 July 2021
DOI: 10.1103/PhysRevMaterials.5.074410

PlumX: Insights into the atomic structure of the interface of ferroelectric Hf_0.5Zr_0.5O₂ grown epitaxially on La_2/3Sr_1/3MnO₃

Epitaxial growth of

{Hf}_{0.5} {Zr}_{0.5} O_{2}

(HZO) thin films allows for the stabilization of the metastable orthorhombic phase with robust ferroelectric properties. So far, the ferroelectric phase is most commonly stabilized on perovskite substrates upon insertion of a buffer layer of

{La}_{2 / 3} {Sr}_{1 / 3} Mn O_{3}

(LSMO).

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Symmetry mode analysis of distorted polar/nonpolar structures in A-site ordered SmBaMn2O6 perovskite

Written on 13 August 2021.

Título : Symmetry mode analysis of distorted polar/nonpolar structures in A-site ordered SmBaMn₂O₆ perovskite

Autores:

J. Blasco, G. Subías, J. L. García Muñoz, F. Fauth, M. C. Sánchez, and J. García

Citation and DOI:

Phys. Rev. B 103, 214110 – Published 21 June 2021
DOI: 10.1103/PhysRevB.103.214110

PlumX: Symmetry mode analysis of distorted polar/nonpolar structures in A-site ordered SmBaMn₂O₆ perovskite

We present a comprehensive structural study of the charge-orbital ordering and magnetic phase transitions observed in the

A

-site ordered

SmBa {Mn}_{2} O_{6}

perovskite combining synchrotron radiation x-ray powder diffraction and symmetry-adapted modes analysis. In

SmBa {Mn}_{2} O_{6}

, successive phase transitions in charge, spin, and lattice degrees of freedom take place with decreasing temperature at

T_{CO 1} \approx 380 K, T_{CO 2} \approx 190 K

, and

T_{N} \approx 250 K

.

Hits: 612

Thickness effect on ferroelectric properties of La-doped HfO2 epitaxial films down to 4.5 nm

Written on 10 August 2021.

Título : Thickness effect on ferroelectric properties of La-doped HfO₂ epitaxial films down to 4.5 nm

Autores: Tingfeng Song, Romain Bachelet, Guillaume Saint-Girons, Nico Dix, Ignasi Fina and Florencio Sanchez

Citation and DOI: J. Mater. Chem. C, 2021,
DOI: 10.1039/D1TC02512K

PlumX: Thickness effect on ferroelectric properties of La-doped HfO₂ epitaxial films down to 4.5 nm

Stabilization of the orthorhombic phase of HfO₂ with La allows very high polarization and endurance. However, these properties have not been confirmed yet in films having thickness of less than 10 nm. We have grown (111)-oriented La (2 at%) doped epitaxial HfO₂ films on SrTiO₃(001) and Si(001) substrates, and we report on the thickness dependence of their ferroelectric properties.

Hits: 633

Optical Plasmon Excitation in Transparent Conducting SrNbO3 and SrVO3 Thin Films

Written on 27 July 2021.

Título : Optical Plasmon Excitation in Transparent Conducting SrNbO₃ and SrVO₃ Thin Films

Autores: Mathieu Mirjolet, Mikko Kataja, Tommi K. Hakala, Philipp Komissinskiy, Lambert Alff, Gervasi Herranz, Josep Fontcuberta

Citation and DOI: Adv. Optical Mater. 2021, 2100520.
DOI: 10.1002/adom.202100520

PlumX: Optical Plasmon Excitation in Transparent Conducting SrNbO₃ and SrVO₃ Thin Films

From catalysis and flat panel displays to photovoltaics, transparent and conducting transition metal oxides are gaining momentum toward more sustainable and cost-efficient applications.

Here it is shown that, without using phase-matching arrangements, bulk plasmons can be excited in continuous epitaxial films of metallic SrVO₃ and SrNbO₃, with plasma absorption edges at visible range, and tuned mainly by electron correlations and phonon dressing. Films can be made reflective or transparent at whish.

Hits: 549

Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO3

Written on 20 July 2021.

Título : Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO₃

Autores: Mathieu Mirjolet, Francisco Rivadulla, Premysl Marsik, Vladislav Borisov, Roser Valentí, Josep Fontcuberta

Citation and DOI: Adv. Sci. 2021, 2004207.
DOI: https://doi.org/10.1002/advs.202004207

PlumX: Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO3

The nature of electron-electron and electron-lattice interactions in metallic oxides is revised. The common wisdom is that the strong correlations among electrons determine their properties. Here we argue that the unavoidable coupling between free electrons and the lattice in ionic materials leads to the formation of polarons. These are carriers dressed by a lattice distortion that travel with them and largely determine the transport and some optical properties.

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A new density-modification procedure extending the application of the recent |ρ|-based phasing algorithm to larger crystal structures

Written on 13 July 2021.

Título : A new density-modification procedure extending the application of the recent |ρ|-based phasing algorithm to larger crystal structures

Autores: Jordi Rius* and Xavier Torrelles

Citation and DOI: Acta Cryst. (2021). A77, 339-347

PlumX: A new density-modification procedure extending the application of the recent |ρ|-based phasing algorithm to larger crystal structures

The incorporation of the new peakness-enhancing fast Fourier transform compatible ipp procedure (ipp = inner-pixel preservation) into the recently published S_M algorithm based on |ρ| [Rius (2020). Acta Cryst A76, 489–493] improves its phasing efficiency for larger crystal structures with atomic resolution data. Its effectiveness is clearly demonstrated via a collection of test crystal structures (taken from the Protein Data Bank) either starting from random phase values or by using the randomly shifted modulus function (a Patterson-type synthesis) as initial ρ estimate.

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Current-Induced Magnetization Control in Insulating Ferrimagnetic Garnets

Written on 29 June 2021.

Título : Current-Induced Magnetization Control in Insulating Ferrimagnetic Garnets

Autores: Can Onur Avci

Citation and DOI:

Journal of the Physical Society of Japan, 90, 081007 (2021) 10.7566/JPSJ.90.081007

PlumX: Current-Induced Magnetization Control in Insulating Ferrimagnetic Garnets

The research into insulating ferrimagnetic garnets has gained enormous momentum in the past decade. This is partly due to the improvement in the techniques to grow high-quality ultrathin films with desirable properties and the advances in understanding the spin transport within the ferrimagnetic garnets and through their interfaces with conducting materials. In recent years, we have seen remarkable progress in controlling the magnetization state of ferrimagnetic garnets by electrical means in suitable heterostructures and device architectures.

Hits: 572

Stabilization of the Ferroelectric Phase in Epitaxial Hf1–xZrxO2 Enabling Coexistence of Ferroelectric and Enhanced Piezoelectric Properties

Written on 18 June 2021.

Título : Stabilization of the Ferroelectric Phase in Epitaxial Hf_1–xZr_xO₂ Enabling Coexistence of Ferroelectric and Enhanced Piezoelectric Properties

Autores: Tingfeng Song, Huan Tan, Nico Dix, Rahma Moalla, Jike Lyu, Guillaume Saint-Girons, Romain Bachelet, Florencio Sánchez*, and Ignasi Fina*

Citation and DOI:

ACS Appl. Electron. Mater. 2021, 3, 5, 2106–2113

Publication Date:April 22, 2021

DOI: https://doi.org/10.1021/acsaelm.1c00122

PlumX: Stabilization of the Ferroelectric Phase in Epitaxial Hf1–xZrxO2 Enabling Coexistence of Ferroelectric and Enhanced Piezoelectric Properties

Systematic studies on polycrystalline Hf_1–xZr_xO₂ films with varying Zr contents show that HfO₂ films are paraelectric (monoclinic). If the Zr content is increased, films become ferroelectric (orthorhombic) and then antiferroelectric (tetragonal). HfO₂ shows very good insulating properties and it is used in metal-oxide-semiconductor field-effect devices, while ZrO₂ shows good piezoelectric properties, but it is antiferroelectric. In between, Hf_0.5Zr_0.5O₂ shows good ferroelectric properties at the expense of poorer insulating and piezoelectric properties than HfO₂ and ZrO₂, respectively.

Hits: 883

Epitaxial Ferroelectric HfO2 Films: Growth, Properties, and Devices

Written on 25 May 2021.

Título : Epitaxial Ferroelectric HfO₂ Films: Growth, Properties, and Devices

Autores: Ignasi Fina* and Florencio Sánchez*

Citation and DOI:

ACS Appl. Electron. Mater. 2021, XXXX, XXX, XXX-XXX

Publication Date:April 13, 2021

DOI: https://doi.org/10.1021/acsaelm.1c00110

PlumX: Epitaxial Ferroelectric HfO2 Films: Growth, Properties, and Devices

About ten years after ferroelectricity was first reported in doped HfO₂ polycrystalline films, there is tremendous interest in this material and ferroelectric oxides are once again in the spotlight of the memories industry. Great efforts are being made to understand and control ferroelectric properties. Epitaxial films, which have fewer defects and a more controlled microstructure than polycrystalline films, can be very useful for this purpose. Epitaxial films of ferroelectric HfO₂ have been much less investigated, but after the first report in 2015 significant progress has been achieved.

Hits: 748

Structure and phase transitions in A-site ordered RBaMn2O6(R=Pr,Nd) -perovskites with a polar ground state

Written on 14 May 2021.

Título : Structure and phase transitions in A-site ordered R Ba Mn₂O₆(R = Pr, Nd) perovskites with a polar ground state

Autores: J. Blasco,*, G. Subías, M. L. Sanjuán, J. L. García-Muñoz, F. Fauth, and J. García

Citation and DOI: Phys. Rev. B 103, 064105 – Published 18 February 2021
DOI: https://doi.org/10.1103/PhysRevB.103.064105

PlumX: Structure and phase transitions in A-site ordered RBaMn2O6(R=Pr,Nd) perovskites with a polar ground state

We report here a structural study of

R Ba {Mn}_{2} O_{6}

(

R = La

, Pr, and Nd) compounds by means of synchrotron radiation x-ray powder diffraction and Raman spectroscopy. The three compounds are

A

-site ordered perovskites adopting the prototypical tetragonal structure at high temperature. A ferromagnetic transition is observed in the

LaBa {Mn}_{2} O_{6}

sample and the lattice parameters undergo anisotropic changes at

T_{C}

related to the orientation of the magnetic moments.

Hits: 647

Tuning the tilting of the spiral plane by Mn doping in YBaCuFeO5 multiferroic

Written on 23 April 2021.

Título : Tuning the tilting of the spiral plane by Mn doping in YBaCuFeO₅ multiferroic

Autores: Xiaodong Zhanga, Arnau Romaguera, Oscar Fabelo, Francois Fauth, Javier Herrero-Martín, José Luis García-Muñoz

Citation and DOI: Acta Materialia, Volume 206, 2021, 116608, ISSN 1359-6454,
DOI: https://doi.org/10.1016/j.actamat.2020.116608

PlumX: Tuning the tilting of the spiral plane by Mn doping in YBaCuFeO5 multiferroic

The layered perovskite YBaCuFeO₅ (YBCFO) is considered one of the best candidates to high-temperature chiral multiferroics with strong magnetoelectric coupling. In RBaCuFeO₅ perovskites (R: rare-earth or Y) A-site cations are fully ordered whereas their magnetic properties strongly depend on the preparation process. They exhibit partial cationic disorder at the B-site that generates a magnetic spiral stabilized through directionally assisted long range coupling between canted locally frustrated spins.

Hits: 786

New Sensitive and Selective Chemical Sensors for Ni2+ and Cu2+ Ions: Insights into the Sensing Mechanism through DFT Methods

Written on 09 April 2021.

Título : New Sensitive and Selective Chemical Sensors for Ni²⁺ and Cu²⁺ Ions: Insights into the Sensing Mechanism through DFT Methods

Autores: Manuel A. Treto-Suárez, Jorge Tapia, Yoan Hidalgo-Rosa, Dayan Páez-Hernández, Elies Molins, Ximena Zarate*, and Eduardo Schott*

Citation and DOI:

J. Phys. Chem. A 2020, 124, 32, 6493–6503

Publication Date:July 8, 2020

DOI: https://doi.org/10.1021/acs.jpca.0c03834

PlumX: New Sensitive and Selective Chemical Sensors for Ni2+ and Cu2+ Ions: Insights into the Sensing Mechanism through DFT Methods

We report the synthesis and theoretical study of two new colorimetric chemosensors with special selectivity and sensitivity to Ni²⁺ and Cu²⁺ ions over other metal cations in the CH₃CN/H₂O solution. Compounds (E)-4-((2-nitrophenyl)diazenyl)-N,N-bis(pyridin-2-ylmethyl)aniline (A) and (E)-4-((3-nitrophenyl)diazenyl)-N,N-bis(pyridin-2-ylmethyl)aniline (B) exhibited a drastic color change from yellow to colorless, which allows the detection of the mentioned metal cations through different techniques.

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Silicon nanowires as acetone-adsorptive media for diabetes diagnosis

Written on 06 April 2021.

Autores: Francisco De Santiago, José Eduardo Santana, Álvaro Miranda, Luis Antonio Pérez, Riccardo Rurali, Miguel Cruz-Irissona

Citation and DOI: Applied Surface Science, Volume 547, 2021, 149175, ISSN 0169-4332,
https://doi.org/10.1016/j.apsusc.2021.149175

PlumX: Silicon nanowires as acetone-adsorptive media for diabetes diagnosis

Early detection of diabetes, a worldwide health issue, is key for its successful treatment. Acetone is a marker of diabetes, and efficient, non-invasive detection can be achieved with the use of nanotechnology. In this paper we investigate the effect of acetone adsorption on the electronic properties of silicon nanowires (SiNWs) by means of density functional theory.

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Soft‐Chemistry‐Assisted On‐Chip Integration of Nanostructured α‐Quartz Microelectromechanical System

Written on 30 March 2021.

Título : Soft‐Chemistry‐Assisted On‐Chip Integration of Nanostructured α‐Quartz Microelectromechanical System

Autores: Claire Jolly, Andres Gomez, David Sánchez‐Fuentes, Dilek Cakiroglu, Raïssa Rathar, Nicolas Maurin, Ricardo Garcia‐Bermejo, Benoit Charlot, Martí Gich, Michael Bahriz, Laura Picas, Adrian Carretero‐Genevrier

Citation and DOI: Adv. Mater. Technol. 2021, 2000831
DOI: https://doi.org/10.1002/admt.202000831

PlumX: Soft‐Chemistry‐Assisted On‐Chip Integration of Nanostructured α‐Quartz Microelectromechanical System

The development of advanced piezoelectric α‐quartz microelectromechanical system (MEMS) for sensing and precise frequency control applications requires the nanostructuration and on‐chip integration of this material on silicon material.

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Critical Effect of Bottom Electrode on Ferroelectricity of Epitaxial Hf0.5Zr0.5O2 Thin Films

Written on 26 March 2021.

Título : Critical Effect of Bottom Electrode on Ferroelectricity of Epitaxial Hf_0.5Zr_0.5O₂ Thin Films

Autores: Saúl Estandía, Jaume Gazquez, Maria Varela, N. Dix, Mengdi Qian, Raul Solanas, Ignasi Fina and Florencio Sanchez

Citation and DOI:

J. Mater. Chem. C, 9, 3486 - 3492 (2021)
DOI: https://doi.org/10.1039/D0TC05853J

PlumX: Critical Effect of Bottom Electrode on Ferroelectricity of Epitaxial Hf_0.5Zr_0.5O₂ Thin Films

Epitaxial orthorhombic Hf_0.5Zr_0.5O₂ (HZO) films on La_0.67Sr_0.33MnO₃ (LSMO) electrodes show robust ferroelectricity, with high polarization, endurance and retention. However, no similar results have been achieved using other perovskite electrodes so far. Here, LSMO and other perovskite electrodes are compared.

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Metallic Diluted Dimerization in VO2 Tweeds

Written on 19 March 2021.

Título : Metallic Diluted Dimerization in VO₂ Tweeds

Autores: Felip Sandiumenge, Laura Rodríguez, Miguel Pruneda, César Magén, José Santiso, Gustau Catalan

Citation and DOI: Adv. Mater. 2021, 2004374
DOI: https://doi.org/10.1002/adma.202004374

PlumX: Metallic Diluted Dimerization in VO2 Tweeds

Though first order transitions are thought to be abrupt, materials find cunning ways to smooth the jump. Here we show that VO₂ chooses making beautiful tapestries at the atomic scale. To see how, and how they affect its intriguing metal-insulator transition, continue reading:

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Facile Chemical Route to Prepare Water Soluble Epitaxial Sr3Al2O6 Sacrificial Layers for Free‐Standing Oxides

Written on 14 March 2021.

Título : Facile Chemical Route to Prepare Water Soluble Epitaxial Sr₃Al₂O₆ Sacrificial Layers for Free‐Standing Oxides

Autores: Pol Salles, Ivan Caño, Roger Guzman, Camilla Dore, Agustín Mihi, Wu Zhou, Mariona Coll

Citation and DOI: Adv. Mater. Interfaces 2021, 2001643.
DOI: https://doi.org/10.1002/admi.202001643

PlumX: Facile Chemical Route to Prepare Water Soluble Epitaxial Sr3Al2O6 Sacrificial Layers for Free‐Standing Oxides

The growth of epitaxial complex oxides has been essentially limited to specific substrates that can induce epitaxial growth and stand high temperature thermal treatments. These restrictions hinder the opportunity to manipulate and integrate such materials into new artificial heterostructures including the use of polymeric and silicon substrates and study emergent phenomena for novel applications.

Hits: 838

Non-volatile optical switch of resistance in photoferroelectric tunnel junctions

Written on 09 March 2021.

Autores: Xiao Long, Huan Tan, Florencio Sánchez, Ignasi Fina & Josep Fontcuberta

Citation and DOI: Nat Commun 12, 382 (2021).
https://doi.org/10.1038/s41467-020-20660-9

PlumX: Non-volatile optical switch of resistance in photoferroelectric tunnel junctions

In the quest for energy efficient and fast memory elements, optically controlled ferroelectric memories are promising candidates. Here, we show that, by taking advantage of the imprint electric field existing in the nanometric BaTiO₃ films and their photovoltaic response at visible light, the polarization of suitably written domains can be reversed under illumination. We exploit this effect to trigger and measure the associate change of resistance in tunnel devices.

Hits: 794

Rapid Thermal Annealing of Double Perovskite Thin Films Formed by Polymer Assisted Deposition

Written on 23 February 2021.

Título : Rapid Thermal Annealing of Double Perovskite Thin Films Formed by Polymer Assisted Deposition

Autores: Hailin Wang, Carlos Frontera, Benjamín Martínez * and Narcís Mestres *

Citation and DOI: Materials 2020, 13(21), 4966
DOI: https://doi.org/10.3390/ma13214966

PlumX: Rapid Thermal Annealing of Double Perovskite Thin Films Formed by Polymer Assisted Deposition

The annealing process is an important step common to epitaxial films prepared by chemical solution deposition methods. It is so because the final microstructure of the films can be severely affected by the precise features of the thermal processing. In this work we analyze the structural and magnetic properties of double perovskite La₂CoMnO₆ and La₂NiMnO₆ epitaxial thin films prepared by polymer-assisted deposition (PAD) and crystallized by rapid thermal annealing (RTA).

Hits: 985

Local electric-field control of multiferroic spin-spiral domains in TbMnO3

Written on 05 February 2021.

Título : Local electric-field control of multiferroic spin-spiral domains in TbMnO₃

Autores: Peggy Schoenherr, Sebastian Manz, Lukas Kuerten, Konstantin Shapovalov, Ayato Iyama, Tsuyoshi Kimura, Manfred Fiebig & Dennis Meier

Citation and DOI:

npj Quantum Mater. 5, 86 (2020)
DOI: https://doi.org/10.1038/s41535-020-00289-z

PlumX: Metallacarboranes as Photoredox Catalysts in Water

Spin-spiral multiferroics exhibit a magnetoelectric coupling effects, leading to the formation of hybrid domains with inseparably entangled ferroelectric and antiferromagnetic order parameters. Due to this strong magnetoelectric coupling, conceptually advanced ways for controlling antiferromagnetism become possible and it has been reported that electric fields and laser pulses can reversibly switch the antiferromagnetic order.

Hits: 905

Thermal evolution of ferroelectric behavior in epitaxial Hf0.5Zr0.5O2

Written on 15 December 2020.

Título : Thermal evolution of ferroelectric behavior in epitaxial Hf_0.5Zr_0.5O₂

Autores: J. W. Adkins, I. Fina, F. Sánchez, S. R. Bakaul, and J. T. Abiade

Citation and DOI:

Appl. Phys. Lett. 117, 142902 (2020)
DOI: https://doi.org/10.1063/5.0015547

PlumX: Thermal evolution of ferroelectric behavior in epitaxial Hf0.5Zr0.5O2

Herein, we report a cryogenic-temperature study on the evolution of the ferroelectric properties of epitaxial Hf_0.5Zr_0.5O₂ thin films on silicon. Wake-up, endurance, and fatigue of these films are found to be intricately correlated, strongly hysteretic, and dependent on available thermal energy.

Hits: 1113

Engineering Polar Oxynitrides: Hexagonal Perovskite BaWON2

Written on 11 December 2020.

Título : Engineering Polar Oxynitrides: Hexagonal Perovskite BaWON₂

Autores: Dr. Judith Oró‐Solé, Dr. Ignasi Fina, Dr. Carlos Frontera, Dr. Jaume Gàzquez, Dr. Clemens Ritter, Marina Cunquero, Dr. Pablo Loza‐Alvarez, Dr. Sergio Conejeros, Prof. Pere Alemany, Prof. Enric Canadell, Prof. Josep Fontcuberta, Prof. Amparo Fuertes.

Citation and DOI: Angew. Chem. Int. Ed. 2020, 59, 18395 – 18399.
DOI: https://doi.org/10.1002/ange.202006519

PlumX: Engineering Polar Oxynitrides: Hexagonal Perovskite BaWON2

Non‐centrosymmetric polar compounds have important technological properties. Reported perovskite oxynitrides show centrosymmetric structures, and for some of them high permittivities have been observed and ascribed to local dipoles induced by partial order of nitride and oxide.

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Mechanical Softness of Ferroelectric 180° Domain Walls

Written on 02 December 2020.

Autores: Christina Stefani, Louis Ponet, Konstantin Shapovalov, Peng Chen, Eric Langenberg, Darrell G. Schlom, Sergey Artyukhin, Massimiliano Stengel, Neus Domingo, and Gustau Catalan.

Citation and DOI: Phys. Rev. X 10, 041001 – Published 1 October 2020
DOI:https://doi.org/10.1103/PhysRevX.10.041001

PlumX: Mechanical Softness of Ferroelectric 180° Domain Walls

Using scanning probe microscopy, we measure the out-of-plane mechanical response of ferroelectric 180° domain walls and observe that, despite separating domains that are mechanically identical, the walls appear mechanically distinct—softer—compared to the domains.

Hits: 923

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