Accession Number : AD0252178

Title :   THE PRESSURE AND TEMPERATURE DEPENDENCE OF THE FE-57 NUCLEAR MAGNETIC RESONANCE FREQUENCY IN FERROMAGNETIC IRON

Corporate Author : HARVARD UNIV CAMBRIDGE MA CRUFT LAB

Personal Author(s) : BENEDEK, G.B. ; ARMSTRONG, J.

Report Date : 30 DEC 1960

Pagination or Media Count : 1

Abstract : The pressure dependence was measured of the Fe-57 nuclear magnetic resonance frequency V in ferromagnetic iron from 1 to 10,000 kg/sq. cm at 77C, 0C, and 84.2C. From these measurements the volume dependence of V was obtained, providing the correct measurements of V(T) at atmospheric pressure for the effects of thermal expansion. By making a similar correction for the effect of the thermal expansion on the temperature dependence of the saturation magnetization sigma, it was found that, at constant volume, the hyperfine coupling constant A in the relation V equals A times sigma is an explicit function of the temperature. Thus, measurements of the temperature dependence of V, even when corrected to constant volume, do not give accurately the temperature dependence of sigma. The results of a theory based on Stoner's collective electron model for the d electrons is presented to account for the temperature dependence of A. (Author)

Descriptors :   *IRON, *NUCLEAR MAGNETIC RESONANCE, ELECTRONS, FERROMAGNETIC MATERIALS, MAGNETIC FIELDS, PRESSURE, TEMPERATURE.

Distribution Statement : APPROVED FOR PUBLIC RELEASE