Magnetization and neutron diffraction studies on TbCr_1-xMn_xO₃

Polycrystalline TbCr_1-xMn_xO₃ samples (where x = 0, 0.05 and 0.1) were prepared using Ball Milling technique. The phase formation and purity of the samples were examined by recording X-ray diffraction (XRD) patterns using Cu-Kα radiation. Structural studies indicate that the lattice parameters decrease upon Mn-doping. The Rietveld analysis of the neutron diffraction patterns collected at different temperature suggests the G - type antiferromagnetic ordering below Neel temperature. In addition, broad hump like feature at low angle below 70K is observed indicating the presence of short-range ordering in the TbCr_1-xMn_xO₃ system.Temperature dependent magnetization measurement of TbCr_1-xMn_xO₃ reveals the presence of two distinct magnetic transitions corresponding to antiferromagnetic ordering of Cr³⁺ (T_N) at ∼ 157K and spin reorientation transition (T_SR) at ∼ 5K. Increase in Mn - substitution at Cr site results in decrease in T_N whereas increase in T_SR, indicating the change in the magnetic interactions due to Mn- doping. Complex permittivity measurements suggest that with decrease in temperature dielectric constant (έ) and loss factor tanδ decreases dramatically. No dielectric anomaly is observed at T_N and T_SR suggesting absence of the magnetoelectric coupling in the presently studied system. (author)