Enhancement of magnetoelectric coupling in Cr doped MnO.

The effect of Cr doping has been undertaken to investigate its effect on the structural, magnetic, dielectric and magnetoelectric properties of newly discovered multiferroics material α-MnO. The Cr doping modifies the room temperature crystal symmetry i.e. transforms from orthorhombic to cubic symmetry. Similar to α-MnO, two magnetic transitions have been observed in all Cr doped samples. The effect of Cr doping manifested on the low temperature transition. The lower magnetic transition shifted toward higher temperature (25 K for pristine to 40 K for Cr = 10%) whereas the high temperature transition decreases slightly with increasing Cr content. A clear frequency independent transition is observed in temperature dependent complex dielectric measurements for Mn Cr O (0 ⩽ x ⩽ 0.10) samples around high temperature magnetic ordering ∼80 K which corroborate the magnetoelectric coupling in these samples. Interestingly, the magnetodielectric value enhanced significantly with Cr doping and a maximum increase of ∼21% is observed for 10% Cr doped sample at 5 K around 70 kOe magnetic field.