MAGNETIC-PROPERTIES OF HIGHLY DILUTED PDFX, AND PTFEX-ALLOYS .1. MAGNETIZATION AT KELVIN TEMPERATURES

Localized 3 d magnetic moments polarize in palladium and platinum matr ices the Pd 4 d and Pt 5 d conduction electrons in their neighbourhood . This leads to effective ''giant magnetic moments'' In,, We have meas ured the magnetization M(x,B,T) of each nine PdFex and PtFex samples w ith 2 ppm less than or equal to x less than or equal to 260 ppm at 1.6 less than or equal to T less than or equal to 300 K and 0 less than o r equal to B less than or equal to 6.0 T. Our main motivation is to de termine the size of the giant magnetic moments induced by highly dilut ed Fe impurities in both transition metals. From the data, taken in a wide polarization range, 9% less than or equal to M/M(sat) less than o r equal to 93%, we determine the impurity concentrations x, the effect ive moments mu(gm) and the spin quantum number J of the samples by fit ting to the Brillouin function. For PdFex, we find a slight increase o f mu(gm) with concentration from (13 +/- 1.5) mu(B), at x = (2.5 +/- 0 .5) ppm to (16 +/- 1) mu(gm), at x = (220 +/- 30) ppm. For PtFex, the moments are almost constant with mu(gm), = (7.8 +/- 1) mu(B) at x = 2 to 14 ppm and mu(gm) = (8.6 +/- 0.7) mu(B) at x = 75 to 95 ppm. For al l samples we obtain a concentration independent very large or possibly infinite spin quantum number, J greater than or equal to 100, which m eans that the localized giant moments behave as classical ones at T > 1.6 K and Tesla magnetic fields.