MAGNETIC AND CRYSTALLINE PROPERTIES OF GDXLA1-XFESI COMPOUNDS

The magnetic and crystalline properties ore the polycrystalline compou nds GdxLa1-xFeSi (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 tetragon al structure. The temperature dependences of the magnetization and ini tial susceptibility show that ferromagnetic behavior is characteristic of these compounds; the exception is the Pauli paramagnetic LaFeSi. S ubstitution of gadolinium by the nonmagnetic lanthanum leads to a shar p drop in the Curie temperature T-c, and to a reduction in the saturat ion magnetic moment mu(0), effective magnetic moment mu(eff), and para magnetic Curie temperature Theta(p). Measurements on single crystal Gd FeSi imply that the easy magnetization axis of this compound is the c axis and the anisotropy field is H-a similar to 4 kOe. No magnetic mom ent was observed on the iron ion in any of these compounds. (C) 1997 A merican Institute of Physics.