Magnetization reversal in bicrystal media

Abstract

Intergranular interactions and time dependence effects have been studied in CoCrPt/Cr thin films with two different Cr concentrations and different physical grain sizes. The samples have a bicrystal structure in which Co alloy grains, grown onto a Cr underlayer have subgrains with orthogonal c-axes. It was found via the ⌬I method that exchange coupling was predominant in all the films along the circumferential direction. The samples with higher Cr concentration exhibited lower exchange coupling as indicated by the value of d(⌬I)max/dH which was found to correlate with the integrated medium noise. The study of the time dependence effects revealed that higher Cr concentration caused a reduction in activation volumes indicating a higher degree of segregation in the grain boundaries of the films. A correlation is reported between the activation volumes and the domain images of the samples in the ac demagnetized state.

Intercrystallite magnetic interactions and properties of nanostructured magnetic materials (review)

“…[2]. The most complete investigation of intercrystallite magnetic interactions has been carried out for thin film magnetic recording media because of their close connection with hystere sis and recording-readout characteristics of the media [5,[15][16][17][18][19][20]. The currently existing thin film recording media comprise magnetic layers of Co alloys with a thickness of 10-30 nm and grain size of 10-50 nm which are sprayed by the ion plasma method.…”