Host: Luis Hueso

L. C. Phillips¹, R. O. Cherifi¹, V. Ivanovskaya¹, A. Zobelli², I. C. Infante³, E. Lesne¹, E. Jacquet¹, V. Garcia¹, S. Fusil^1,4, P. R. Briddon⁵, N. Guiblin³, A. Mougin², A. A. Ünal⁶, S. Valencia⁶, B. Dkhil³, A. Barthélémy¹  and M. Bibes¹

¹Unité Mixte de Physique CNRS/Thales and Université Paris-Sud, Orsay, France

²Laboratoire de Physique des Solides, Université Paris-Sud, Orsay, France

³Laboratoire SPMS, Ecole Centrale Paris, Châtenay-Malabry, France

⁴Université d?Evry-Val d?Essonne, Evry, France

⁵School of Electrical Engineering, University of Newcastle, Newcastle-upon-Tyne, UK

⁶Helmholtz-Zentrum Berlin, Berlin, Germany

 

Controlling magnetism by electric fields is an important research goal [1,2] with possible applications in spintronics [3]. Despite advances in the electric field control of magnetic anisotropy [4], domain structure [5], spin polarization [6] and critical temperature [7], on-off switching of robust ferromagnetism at room temperature remains to be demonstrated.

The ordered, near-equiatomic phase of the Fe-Rh alloy system is an interesting candidate material because it shows a metamagnetic transition that can be driven by temperature, pressure or magnetic field. We recently used BaTiO₃ (BTO) substrates that are ferroelectric and ferroelastic to dynamically drive the metamagnetic transition in thin FeRh films [8]. The BTO domains can be rearranged by applying only a few volts, and so the system?s effective magnetoelectric coupling constant is the largest yet measured.

Here we use x-ray magnetic circular dichroism (XMCD) contrast in photoemission electron microscopy (PEEM) to show that sub-micron-sized ferromagnetic (F) regions are created in FeRh and coexist with the antiferromagnetic (AF) phase. Detailed ab-initio calculations show that the relative stability of the F and AF phases is tuned primarily by the changes in the pseudocubic lattice parameter of strained FeRh, despite the changes in bond angles that arise due to monoclinic distortions.

Our work opens new avenues for spintronics using ferroelectrics and magnetic materials with first-order phase transitions.

This work received financial support from the French Agence Nationale de la Recherche through project NOMILOPS (ANR-11-BS10-0016) and the European Research Council Advanced Grant FEMMES (contract n°267579).

[1] Vaz, J. Phys. Condens. Matter 24, 333201 (2012)

[2] Fusil et al., Annu. Rev. Mater. Res. 2014, 44:7 (2014)

[3] Chappert et al., Nature Mater. 6, 813 (2007)

[4] Weiler et al., New J. Phys. 11, 013021 (2009)

[5] Ghidini et al., Nature Commun. 4, 1421 (2013)

[6] Garcia et al., Science 327, 1106 (2010)

[7] Chiba et al., Nature Mater. 10, 853 (2011)

[8] Cherifi et al., Nature Mater. 13, 345 (2014)