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Magnetocaloric and structural properties of SmMn2Ge2

2005; Elsevier BV; Volume: 408-412; Linguagem: Inglês

10.1016/j.jallcom.2005.04.181

1873-4669

Keiichi Koyama, S. Miura, Hironari Okada, T. Shigeoka, Shun Fujieda, A. Fujita, K. Fukamichi, K. Watanabe,

Magnetic Properties of Alloys

Abstract We have performed detailed magnetization, specific heat and powder X-ray diffraction measurements under magnetic fields, for obtaining information on the magnetic and the structural properties of re-entrant ferromagnet SmMn 2 Ge 2 with the ThCr 2 Si 2 -type tetragonal structure. The lattice parameter a decreases by about 0.1%, while the parameter c increases slightly by about 0.02% in the antiferromagnetic (AFM) state, compared with the ferromagnetic (FM) and re-entrant ferromagnetic (RFM) states. In the AFM state, the structural distortion recovers by applying a magnetic field, accompanied with the metamagnetic transition from the AFM to the forced FM states. The results of a magnetocaloric effect indicate that the magnetic entropy change at these phase transitions is mainly due to the change of the Sm magnetic state.