Resistivity and magnetization in disordered crystalline compound seriesR(AlxM1−x)2 (R=rareearth;M=Cu,Co,Fe)

Electrical resistivity promises to be capable of partly elucidating various important aspects of the phenomenology within the complex field of amorphous-type magnetism in crystalline solids (clamor magnets). For this purpose resistivity measurements were carried out on such partly disordered crystalline pseudobinary compound series as $R{\left({\mathrm{Al}}_x{\mathrm{Co}}_{1-x}\right)}_2$, $R{\left({\mathrm{Al}}_x{\mathrm{Fe}}_{1-x}\right)}_2$, and $(R_1,R_2){\mathrm{Al}}_2$, where $R=\mathrm{Gd},\mathrm{Y}$, or an anisotropic rare earth. Compared to the binaries $R{\mathrm{Al}}_2$, the relative decrease of resistivity below the magnetic-ordering temperatures of the disordered materials is much smaller for materials based on anisotropic rare earths, and it is also quite weak in those based on Gd. This indicates a considerable influence of exchange fluctuations for the genesis of magnetic clamor states. Selected high-field magnetization measurements are also shown to corroborate a partly disordered magnetic state below the ordering temperature. Some discussion is given to the relationship of crystalline and amorphous magnetic materials.