Magnetoelectric coupling tuned by competing anisotropies inMn1−xNixTiO3

Songxue Chi, Feng Ye, H. D. Zhou, E. S. Choi, J. Hwang, Huibo Cao, Jaime A. Fernandez-Baca
2014 Physical Review B  
A flop of electric polarization from P∥c (P_c) to P∥a (P_a) is observed in MnTiO_3 as a spin flop transition is triggered by a c-axis magnetic field, H_c=7 T. The critical magnetic field H_c for P_a is significantly reduced in Mn_1-xNi_xTiO_3 (x=0.33). P_a and P_c have been observed with both H_c and H_a. Neutron diffraction measurements revealed similar magnetic arrangements for the two compositions where the ordered spins couple antiferromagnetically with their nearest intra- and inter-planar
more » ... neighbors. In the x=0.33 system, the uniaxial and planar anisotropies of Mn^2+ and Ni^2+ compete and give rise to a spin reorientation transition at T_R. A magnetic field, H_c, aligns the spins along c for T_R<T<T_N. The rotation of the collinear spins away from the c-axis for T<T_R alters the magnetic point symmetry and gives rise to a new ME susceptibility tensor form. Such linear ME response provides satisfactory explanation for the behavior of the field-induced electric polarization in both compositions. As the Ni content increases to x=0.5 and 0.68, the ME effect disappears as a new magnetic phase emerges.
doi:10.1103/physrevb.90.144429 fatcat:6tvp3nyltjafrf3lg6utovsyua