Observation of re-entrant spin reorientation in TbFe(1−x)Mn(x)O(3)

We report a spin reorientation from Γ(4)(G(x), A(y), F(z)) to Γ(1)(A(x), G(y), C(z)) magnetic configuration near room temperature and a re-entrant transition from Γ(1)(A(x), G(y), C(z)) to Γ(4)(G(x), A(y), F(z)) at low temperature in TbFe(1−x)Mn(x)O(3) single crystals by performing both magnetization and neutron diffraction measurements. The Γ(4) − Γ(1) spin reorientation temperature can be enhanced to room temperature when x is around 0.5 ~ 0.6. These new transitions are distinct from the well-known Γ(4) − Γ(2) transition observed in TbFeO(3), and the sinusoidal antiferromagnetism to complex spiral magnetism transition observed in multiferroic TbMnO(3). We further study the evolution of magnetic entropy change (−ΔS(M)) versus Mn concentration to reveal the mechanism of the re-entrant spin reorientation behavior and the complex magnetic phase at low temperature. The variation of −ΔS(M) between a and c axes indicates the significant change of magnetocrystalline anisotropy energy in the TbFe(1−x)Mn(x)O(3) system. Furthermore, as Jahn-Teller inactive Fe(3+) ions coexist with Jahn-Teller active Mn(3+) ions, various anisotropy interactions, compete with each other, giving rise to a rich magnetic phase diagram. The large magnetocaloric effect reveals that the studied material could be a potential magnetic refrigerant. These findings expand our knowledge of spin reorientation phenomena and offer the alternative realization of spin-switching devices at room temperature in the rare-earth orthoferrites.