Ab initio study of the magnetoelectric coupling in BaTiO3/CaMnO3 thin film heterostructures

DI NAPOLI, S.

Uppsala

Simposio; Joint European Magnetic Symposia; 2019

Uppsala University - European Magnetism Association

Oneroute towards the development of multiferroic materials with strongmagnetoelectric coupling is by exploring the break of time reversaland space inversion symmetries that occur at the interface between amagnetic and a ferroelectric material. The properties of eachcomponent of the heterostructures can be chosen within a large numberof materials, allowing a better optimization of the desiredproperties. This engineered magnetoelectric coupling could reachvalues that are orders of magnitude larger than those typical ofsingle phase multiferroics. Inthis work the structural, electronic and magnetic properties ofBaTiO3/CaMnO3heterostructures grown on an SrTiO3 substrate areinvestigated from first principles calculations. The most importanteffects to take into account when dealing with the electronic andmagnetic properties of thin films of ferroelectric/magnetic heterostructures can be mechanical strain, charge transfer andinterface effects. Therefore we study how the epitaxial tensilestrain induced by the substrate and the confinement affect themagnetic properties of CaMnO3thin films for both, MnO2- and CaO-terminated surfaces. Wefind that when the film is CaO-terminated the magnetic structureremains equal to the bulk one (antiferromagnetic coupling between Mnnearest neighbours, i.e. GAF) whereas a MnO2-terminatedfilm favors an in-plane ferromagnetic coupling between Mn atoms.Finally,we also analyze the influence of the BaTiO3polarization switching by means of the charge transferthrough the interface for different interface combinations, namelyBaO-MnO2 andTiO2-CaO.p { margin-bottom: 0.1in; line-height: 115%; }