Structural and magnetic properties of DyCo4_xFexGa compounds

摘要

The structural and magnetic properties of the DyCo_(4-x)Fe_xGa compounds with x=0, 0.5, 1, and 1.5 have been investigated by X-ray diffraction and magnetic measurements. Powder X-ray diffraction analysis reveals that each of the DyCo_(4-x)Fe_x.Ga compounds has a hexagonal CaCu_5-type structure (space group P6/mmm). The Fe solubility limit in DyCo_(4-x)Fe_xGa is x< 1.5. The higher the value of x, the larger the unit-cell parameters a, c, V, and the 3d-sublattice moment but the smaller the 3d uniaxial anisotropy. Magnetic measurements show that the Curie temperature of DyCo_(4-x)Fe_xGa increases from 498 K for x=0 to 530 K for x=1.5, the compensation temperature T_(comp) decreases from 286 K for x=0 to 238 K for x= 1.5, and the spin-reorientation transition temperature increases from 403 K for x=0 to 530 K for x=0.5. No spin-reorientation transition was found in the samples with x=1.0 and 1.5. The saturation magnetization of DyCo_(4-x)Fe_xGa measured at 173 K increases but the magnetization measured at 300 K decreases with increasing Fe content x.