Thermoremanent magnetization. I. Experiments on single domain grains

Abstract

This paper describes an attempt to test certain predictions by Néel concerning the properties of thermoremanent magnetization in fine-grained materials. The method of investigation was to examine the effects of alternating-field demagnetization on a specimen which had been given partial and total thermoremanences.

A positive correlation was found between the blocking temperature and coercive force of individual magnetic grab in accordance with a prediction of Néel's. In confirmation of another of Néel's predictions, the ratio j_T/j_s of thermoremenence to spontaneous magnetization in grain6 with a particular blocking-temperature T_B was found to be proportional to the hyperbolio tangent of the magnetizing field; whilst in apparent disagreement with a third prediction j_T/j_s was found to be independent of the coercive force of the grains. In addition the blocking temperatures were found to be almost independent of the magnetizing field up to 50 oersteds.