The magnetocrystalline anisotropy of cobalt

Abstract

Recent high precision measurements of the uniaxial anisotropy constants K 1 and K 2 are reported taken from three samples grown by different techniques. The results vindicate the early work of Succksmith and Thompson and agree well with the recent measurements of Ono. While some variation was observed between results from the three samples we conclude that these are insufficient to account for the spread of results in the literature and suggest inaccurate shearing corrections as the most probable cause of discrepancy. A very good fit to the K 1 data was obtained using a single ion model and the c/a ratio as an adjustable parameter. These c/a values gave a satisfactory fit to K 2 and also lay within the scatter of the experimentally measured c/a values. However, a definitive test of the single ion theory was not possible due to these experimental uncertainties in c/a. Data for the temperature variation of the basal plane anisotropy constant K 4 are reported for the first time. The single ion model predictions are not in very good agreement with the K 4 data.