ATTENTION !!! CHANGEMENT DE SALLE ET D’HORAIRE !!! Magneto(di)electric Effect in Spinel Oxides

Orateur : A. SUNDARESAN (Jawaharlal Nehru Centre for Advanced Scientific Research - Jakkur - Bangalore - India)

Electric field control of magnetism in materials has received much attention in recent years because of its potential for technological applications. Several materials exhibiting magnetoelectric effect (mutual control of electric polarization with magnetic field or magnetization with electric field) below the magnetic ordering temperature have been discovered. In my talk, I will present the discovery of linear magnetoelectric effect in several A-site antiferromagnetic oxides, Co3O4, CoAl2O4 and MnB2O4 (B = Al, Ga), which belong to the family of AB2O4 oxides with spinel structure (Fdm). In these normal spinels, the magnetic ions (Co2+ and Mn2+) located at the A-site, undergo collinear antiferromagnetic ordering at low temperatures. A dielectric anomaly and electric polarization appear at the Neel temperature only when an external magnetic field is applied. The observation of linear magnetoelectric effect in these spinels is consistent with the magnetic point symmetry () according to the easy axis along [111] direction. I shall also discuss about magnetodielectric properties in A-site ordered Chromite spinels, LiMCr4O8 (M=Ga, In and Fe).

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