We have investigated the multiferroicity and magnetoelectric (ME) coupling in HoFeWO6. With a noncentrosymmetric polar structure (space group Pna21) at room temperature, this compound shows an onset of electric polarization with an antiferromagnetic ordering at the Néel temperature (TN) of 17.8 K. The magnetic properties of the polycrystalline samples were studied by DC and AC magnetization and heat capacity measurements.
The metamagnetic behavior at low temperatures was found to be directly related to the dielectric properties of the compound. In particular, field-dependent measurements of capacitance show a magnetocapacitance (MC) effect with double-hysteresis loop behavior in direct correspondence with the magnetization. Our x-ray diffraction results show the Pna21 structure down to 8 K and suggest the absence of a structural phase transition across TN. Soft x-ray absorption spectroscopy and soft x-ray magnetic circular dichroism (XMCD) measurements at the Fe L2,3 and Ho M4,5 edges revealed the oxidation state of Fe and Ho cations to be 3+. Fe L2,3 XMCD further shows that Fe3+ cations are antiferromagnetically ordered in a noncollinear fashion with spins arranged 90∘ with respect to each other. Our findings show that HoFeWO6 is a type-II multiferroic exhibiting a MC effect. The observed MC effect and the change in polarization by the magnetic field, as well as their direct correspondence with magnetization, further support the strong ME coupling in this compound.
Oxides for new-generation electronics
Magnetocapacitance effect and magnetoelectric coupling in type-II multiferroic HoFeWO6
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