Effects of ZrO2 on the structure and magnetic properties of CoPt thin films

[CoPt1.5nm/ZrO2 xnm]10 multilayer films were deposited on glass substrates by magnetron sputtering and then annealed in vacuum at 600°C for 30 min. Their structures and magnetic properties were investigated as a function of ZrO2 content. The results show that the grain size and coercivity first increase and then decrease with the increase in ZrO2 content. The maximum coercivity and grain size are obtained at 37 vol.% of ZrO2. The content of ZrO2 in the film plays an important role in the separation of CoPt grains and in the reduction of intergrain exchange interaction. On the basis of the studies of angular dependent coercivity, it is found that the magnetization reversal of CoPt films with (111) texture is different from either the domain wall motion or the S-W type of rotation mode.