Mengdi arrived from China with a CSC scholarship to carry out her PhD thesis under the supervision of Prof. Josep Fontcuberta and Dr. Ignasi Fina. Since then, she has not only done some great research, but she has also learnt Spanish, and loves living and spending time with locals. Many of her friends from Cerdanyola came to see her PhD Thesis defense on Friday, 16 November. 

In the photo, Mengdi appears with her two supervisors, and with the three members of the PhD Committee, Francesca Campabadal, from the IMB-CNM-CSIC, Catherine Dubourdieu, from the Freie Universität Berlin/Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany and Stefano Brivio, from the Consiglio Nazionale delle Ricerche (CNR, National Research Council) – Institute for Microelectronics and Microsystems (IMM) in the Unit of Agrate Brianza, Italy.

Resistive switching in nanometric BaTiO₃ ferroelectric junctions

Date: Friday, 16 November 2018
Time: 10 am
Venue: Sala d'Actes Carles Miravitlles, ICMAB

Abstract: Ferroelectric capacitors consisting in two metallic electrodes separated by a ferroelectric layer have great potential for memory and logic devices. Naturally, the success of this approach relies on the ability to build ferroelectric capacitor displaying large resistance changes (resistive switching, RS) at room temperature.The goal of the present thesis is the study of the RS behavior of ferroelectric thin (10-100 nm) and ultrathin (<10 nm) films. In particular, we study the different RS response depending on parameters such as ferroelectric layer thickness, writing voltage, amplitude and polarity, writing time, device temperature and contact configuration. We argue that the presence of imprint electric fields causes the device asymmetry. We discovered that the magnitude and sign of RS depend on the barrier thickness and writing protocol. We experimentally demonstrated that using a simple anti-serial connection of ferroelectric tunnel junctions has significant advantages in power saving. 

 Supervisors:

• Josep Fontcuberta, Laboratory of Multifunctional Oxides and Complex Structures (MULFOX), ICMAB
• Ignasi Fina, Laboratory of Multifunctional Oxides and Complex Structures (MULFOX), ICMAB

• President: Francesca Campabadal, IMB-CNM-CSIC, Spain
  
• Secretary: Catherine Dubourdieu, Freie Universität Berlin/Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany
  
• Vocal: Stefano Brivio, Consiglio Nazionale delle Ricerche (CNR, National Research Council) – Institute for Microelectronics and Microsystems (IMM) in the Unit of Agrate Brianza, Italy