Structural and magnetic properties of Gd5SixSn4-x -: art. no. 214413

The ternary Gd5SixSn4-x alloy system has been shown to exist for all x. Structural and magnetic phase diagrams have been derived. Si-rich and Sn-rich alloys are orthorhombic and order ferromagnetically, with T-c increasing with Si content. Intermediate compositions are monoclinic, and exhibit a disordered noncollinear magnetic order. In the ordered state, Sn-119 Mossbauer spectroscopy shows transferred hyperfine fields approaching 37 T at Sn sites in the orthorhombic form, and severely broadened spectra with much smaller fields in the monoclinic form. For xless than or equal to0.4, there is, on heating, a first-order magnetic and structural transition from a ferromagnetic to a nonmagnetic state that may be associated with a giant magnetocaloric effect.