Experimental and theoretical analysis of rotational hysteresis loss in CoCrTa perpendicular recording media

We measured the value of rotational hysteresis loss W-r for various CoCrTa perpendicular media, and discussed the dependence of W-r and the hysteresis integral R-h On the perpendicular anisotropy and the strength of intergran ular exchange coupling. Simulated results using a model based on the Landau -Lifshitz-Gilbert equation were compared with the experimental results. The experimental and theoretical studies revealed that improvement of the c-ax is alignment significantly reduces W-r, resulting in a small R-h value of s imilar to 0,2, increase of intergranular exchange coupling shifts the appli ed field at which W-r reaches a maximum, H-p, to a lower field and produces a large R-h. Decrease of K-u also shifts H-p to a lower field but is accom panied by a reduction of R-h. These results imply that the values of R-h an d H-p are strongly related to the structural and magnetic properties, and a nalysis of rotational hysteresis loss appears to be a useful technique to c haracterize perpendicular media.