MAGNETIC-PROPERTIES OF THE PSEUDOBINARY SOLID-SOLUTION GDGA1-XGEX O-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1)

A solid solution of tile binary phases GdGa and GdGe was found investi gating the phase equilibria in the pseudobinary system GdGa1-xGex (0 l ess than or equal to x less than or equal to 1) at T = 800 degrees C X -ray powder diffraction patterns terns proved a C-orthorhombic unit ce ll (CrB-type). The results of the magnetic measurements reveal: a) GdG a is a simple ferromagnet, b) samples for 0 < x < 0.5 show a metamagne tic behavior, c) the alloys x greater than or equal to 0.5 and GdGe ar e antiferromagnets. Applying the RKKY theory to tile GdGa1-xGex system infers that the magnetic properties strongly depend on the conduction electron density at the Fermi level. Measurements of the electrical r esistivity qualitatively support this assumption.