Domain structures and magnetic anisotropy of TbFe12-xTix single crystals

The domain structures of TbFe12-xTix (x=0.85, 1.0, and 1.3) single crystals in different crystal planes have been investigated using magnetic force microscopy. The patterns with large contrast are observed in (1 1 0) and (1 0 0) planes for the samples of x=0.85, while the slight contrast is detected in (0 0 1) plane, indicating the anisotropy is easy plane. By increasing x to 1.0 and 1.3, the domain structures change dramatically in (1 1 0), (1 0 0), and (0 0 1) planes. This demonstrates that the anisotropy transforms from easy plane to easy axis, which is related to spin reorientation and the strong magneto-crystalline anisotropy in the basal plane. The calculation of the domain patterns according to the Hubert model shows that the domains are the branching outcome of the basic domains.