Magnetic and crystalline properties of GdxLa1?x FeSi compounds

The magnetic and crystalline properties of the polycrystalline compounds Gd_xLa_1−x FeSi (x=0, 0.1, 0.3, 0.45, 0.55, 0.65, 0.8, 1) and single crystal GdFeSi are studied. All the compounds have the CeFeSi tetragonal structure. The temperature dependences of the magnetization and initial susceptibility show that ferromagnetic behavior is characteristic of these compounds; the exception is the Pauli paramagnetic LaFeSi. Substitution of gadolinium by the nonmagnetic lanthanum leads to a sharp drop in the Curie temperature T _c, and to a reduction in the saturation magnetic moment μ ₀, effective magnetic moment μ _eff, and paramagnetic Curie temperature Θ_p. Measurements on single crystal GdFeSi imply that the easy magnetization axis of this compound is the c axis and the anisotropy field is H _a∼4 kOe. No magnetic moment was observed on the iron ion in any of these compounds. Fiz. Tverd. Tela (St. Petersburg) 39, 325–329 (February 1997)