Effect of nitrogen on the high coercivity and microstructures of Cohyphen;Ni alloy films

摘要

Cohyphen;30 at.thinsp;percnt; Ni alloy films containing N up to 18 at.thinsp;percnt; were deposited to thicknesses of 100 and 400 nm by rf sputtering in the atmosphere of Arhyphen;N2mixture and they were annealed. Most of N included diffused out from the film surface after annealing. The concentration of N, (Cnf) before annealing, however, has a significant effect on the coercive force,Hc, and the formation of the microstructures such as hollow channels andcaxis preferred orientation parallel to the film plane in the annealed films. The preferred orientation factor,R, has a minimum, andHchas a maximum in a film withCnfof 13ndash;15 at.thinsp;percnt;. There is a linear relation betweenHcandR;Hc=Hc0(1minus;R/R0). The values ofHc0tend to decrease with the film thickness, and they slightly depend on the microstructures, such as the hollow channels and grain boundaries.