Influence of an external magnetic field on nuclear resonance in ferromagnetic materials

Abstract

The reduction in the amplitude of the nuclear magnetic resonance signal, as well as a change in line shape, upon the application of an external steady magnetic field has been measured for metallic nickel at room temperature. Both the transverse and longitudinal configurations (steady field and rf field perpendicular and parallel, respectively) were measured for a sample of nickel powder and for bulk nickel. The signal amplitude drops faster in the longitudinal configuration than in the transverse for each specimen. The reduction in amplitude is considerably less for the pellets than for the powder. There is no sign of a critical field as previously reported. A comparison of the resonance results with the apparent permeabilities is presented. The difference in behavior of the nuclear resonance signal for the transverse and longitudinal configurations is related directly to the difference in the behavior of the permeabilities for the two configurations. © 1966 The American Institute of Physics.