Spin cluster glass and magnetoelectricity in Mn-doped KTaO3.

In ceramics of KTaO3. doped with 3 at. % of Mn the dielectric response is dominated by the polydispersive behavior of Mn2+ centered polar regions, whereas the magnetic and magnetoelectric (ME) behaviors reflect an intimate coupling between A-site substituted Mn2+ ions and minute amounts of Mn3O4 precipitates mediated by the polar host material. This becomes apparent by the common onset at T-c approximate to 42 K of the ordering of ferrimagnetic Mn3O4 and of a spin cluster glass, which is characterized by memory and rejuvenation effects. The composite magnetic system exposed to external magnetic and electric dc fields shows large third order ME susceptibility with a sharp anomaly at T-c and 1/T-2 dependence as T -> 0. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3430990]