NMR Study of ⁵⁹Co in Gd_1−xY_x (Fe_.7Co_.3)₂ and Gd_1−xY_x (Fe_.5Co_.5)₂

Abstract

Nuclear magnetic resonance of ⁵⁹Co nuclei in Gd_1−xY_x(Fe_.7Co_.3)₂ and Gd_1−xY_x(Fe_.5Co_.5)₂ has been observed at 77 K as a function of Y concentration. The contribution of 4f electrons of Gd atoms to the hyperfine fields is estimated as at most 10 kOe in these two systems. This value is interpreted as the sum of the change in three kinds of contributions caused by Y substitution; the core polarization in the central Co atom, the conduction electron polarization arising from nearest neighbor Fe and Co atoms and the transferred hyperfine field from neighboring Gd atoms. The temperature dependence of resonance frequencies in Gd(Fe_.7Co_.3)₂ and Gd(Fe_.5Co_.5)₂ has also been measured.