Study on Improvement of Magneto-optical Characteristics of Ferromagnetic Heusler Alloy Films with Artificial Lattice Deposited by Sputtering.

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Since a PtMnSb heusler alloy with a Clb type of crystal structure is well known to have an extremely large magneto optical Kerr rotation angle K, its magnetic characteristics are interesting theoretically and its thin films are candidates for magneto-optical recording media. Recently, several studies on the preparation of PtMuSb thin films with large K by sputtering and vacuum evaporation have been carrried out.However, they haave not yet had sufficient perpendicular anisotropy to be used for practical applications such as magneto-optical recording media.On the other hand several studies on the possibility of realizing perpendicular anisotropy have been performed. It has been, for example, reported that destinguishable perpendicular anisotropy may be induced in several atomic layers in the vicinity of interfaces of the ferromagnetic layer and non-magnetic layer in multilayered films.In this study, the preparation of Pt/MnSb multilayered films with outstanding perpendicular anisotropy c … More omposed of Pt layers and MnSb ones by using Facing Targets Sputtering apparatus has been attempted and their crystallographic and magnatic characteristics have been investigated in detail.Pt/MnSb multilayered films have been prepared by using a Facing Targets Sputtering apparatus to investigate magnetic characteristics, especially, perpendicular anisotropy of films with large magneto-optical Kerr rotation angle k. Pt layers and MnSb ones were alternately deposited on a glass slideat a substrate temperature off 200゜C. The saturation magnetization Ms and the coercive force Hc of them depend strongly on the ratio in thickness of the Pt layer to bilayer (Pt layer + MnSb layer) thickness. Ms is a maximum of 550゜C emu/cc in annealed films. Some films annealed at 400゜C for 150 minutes in vacuum exhibit significant perpendicular anisotropy. For example, a 2000゜A-thick Pt/MnSb multilayered film composed of 50A-thick MnSb layers and about 13\thick Pt ones had perpendicular anisotropy constant Ku of 4x10^5 erg/cc. Consequently, these films may be excellent candidates used as a new type of magneto-optical recording media with large output signals. Less