Study of ferromagnetic correlations caused by impurities in nonmagnetic materials by the method of small-angle scattering of polarized neutrons

Abstract

The possibility of the study of ferromagnetic correlations caused by d-metal impurities in nonmagnetic matrices is discussed. The polarization and magnetic-nuclear interference obtained by analyzing the small-angle scattering of polarized neutrons in a CuZn(20) alloy with Ni impurity (1 at %) are reported. It has been shown that Ni is clustered in the CuZn matrix with the characteristic correlation radius in the range 100 A < Rc < 5000 A depending on the thermal processing of the samples. The cross correlation function determining magnetic-nuclear interference is satisfactorily approximated by the exponential exp(−r/Rc), where r is the distance. It has been found that the nonmagnetic matrix CuZn(20) with an almost uniform distribution of 1% Ni impurity has metamagnetic properties in the field H ≈ 0.5 T at room temperature.