Magnetic Lag and Anisotropy Due to Interstitials in fcc Ferromagnetic Alloys

Abstract

In fcc alloys, carbon and other interstitials occupy octahedral sites and hence were long believed to cause no lag, except for pairs of interstitials. In contrast to this the authors have recently found strong lag and anisotropy caused by single interstitials of carbon, hydrogen, and nitrogen. It is shown that this lag is due to the fact that in fcc solid solutions the environment of octahedral sites is noncubic. The induced anisotropy increases linearly with interstitial content. The symmetry axis of lattice defects are preferably the 〈100〉 directions in nearly pure metals and 〈110〉 and 〈111〉 directions in binary alloys with a high concentration of substitution solute atoms. In pure metals, induced anisotropy is only a small residual effect. The paper includes: Theory of this lag; experimental data of disaccomodation behavior; determination of activation energy; comparison with damping experiments and theories; aspects for technically useful materials.