Mossbauer spectroscopy study of short-range magnetic ordering in Co–Ga (Fe⁵⁷) intermetallic compounds

Abstract

The magnetic state of a transition-metal impurity in a metallic matrix is determined mainly by the local atomic environment of the impurity. Further, even the ferromagnetic properties of certain intermetallic compounds, as monitored by macroscopic measurements, seem to be governed by the local atomic environment effects. Microscopic Mossbauer measurements on Co–Ga alloys containing dilute quantities of Fe impurities reveale the presence of both magnetic and nonmagnetic regions in the alloys, containing more than 50 at% Co atoms, depending upon the local atomic environments. The Mossbauer spectra observed give evidence for the occurrence of short-range magnetic ordering in these alloys. The experimental results and existing magnetization data seem to indicate that the Co–Ga alloys exhibit “mictomagnetic” behaviour characteristic of disordered alloys.