Ag/[BN/CoPt]5/Ag and [BN/Ag/CoPt]5/Ag thin films were deposited on glass substrates by magnetron sputtering and then annealed in vacuum at 600 ℃ for 30 min.The structures and magnetic properties of CoPt/BN multilayer films were investigated as a function of Ag layer thickness.It was found that the face-centered tetragonal (fct) (001) texture of CoPt was improved greatly by introducing the Ag toplayer or sublayer together with an Ag underlayer.Good (001)-oriented growth,low intergrain interactions as well as high perpendicular anisotropy can be obtained in the Ag(3 nm)/[BN(2.5 nm)/CoPt(3 nm)]5/Ag(7 nm) and [BN(2.5 nm)/Ag(2 nm)/CoPt(3 nm)]5/Ag(10 nm) films,which become potential candidates for ultrahigh density magnetic recording media.
[CoPt 1.5 nm/ZrO2 x nm]10 multilayer films were deposited on glass substrates by magnetron sputtering and then an-nealed 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 impor-tant 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.
SHEN Xiaohua XU Xiaohong JIANG Fengxian LV Baohua TIAN Baoqiang JIN Tao
FePt (50 nm) and [FePt(a nm)/MgO(b nm)]5/glass (a=1, 2, 3; b=1, 2, 3) films were prepared by radio frequency (RF) magnetron sputtering technique, and then were annealed at 600°C for 30 min. The effect of MgO layer thickness on the structures and magnetic properties of the FePt/MgO multilayers was investigated. The coercivities and inter-grain interactions of the FePt/MgO films were decreased, yet the degree of (001) texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FePt/MgO films with appropriate coercivities, high perpendicular anisotropy, and weak in-ter-grain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FePt/MgO nanos-tructured films are promising candidates for future high-density perpendicular recording media.
[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO2/FePt]5/Ag films are changed into L10 and (111) mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 (0.6 nm)/FePt (3 nm)]5/Ag (50 nm) films and highly (001)-oriented films can be obtained in the [SiO2 (2 nm)/FePt (3 nm)]5/Ag (50 nm) films.
