Sign of the Magnetic Hyperfine Field in Dilute Iron Alloys Using the Mössbauer Effect

Abstract

The sign of the hyperfine field in several dilute iron alloys has been determined. The technique makes use of the Mössbauer effect, which is used to establish the helicity of gamma rays emitted and absorbed in a longitudinal magnetic field. Experiments were performed which show that the field induced at the iron nucleus by the application of an external magnetic field $H_0$ is negative (i.e., opposite to $H_0$) in Mössbauer sources of ${\mathrm{Co}}^{57}$ in Cu and Au and in absorbers of Mo and Rh containing about 1% ${\mathrm{Fe}}^{57}$. The spontaneous field $H_{\mathrm{int}}$ observed in a ½% ${\mathrm{Fe}}^{57}$-in-Cr alloy below 50°K is positive.