Song Sheng Xue

The Effect of Underlayer NIFEX on the Magnetic Propertiesof The Copt Films

The effects of soft magnetic underlayer, NiFeX, on the magnetic properties of CoPt films has been studied as a function of substrate bias and Ar pressure during the NiFeX deposition and sputter etch time prior to the CoPt film deposition. It is concluded that the FCC (111) texture of NiFeX plays a dominant role in the c-axis orientation of CoPt films, Applying substrate bias or using P-Ta as an underlayer, the FCC (111) texture of NiFeX films can be greatly enhanced. Applying no substrate bias and sputtering at high Ar pressure, the FCC (111) texture of NiPeX films can be suppressed. As a consequence, the anisotropy of the CoPt films can be made either in-plane or perpendicular depending on the crystallinity of the NiPeX films. It is also found that a strong ferromagnetic exchange field between NiPeX and CoPt films favors the growth of CoPt films with c-axis in-plane, with a typical symptom of high in-plane moment thickness product and low remnant coercivity.

Thin soft sendust laminated CoPt hard films

The C-axis of the Co-based permanent magnet films tends to grow gradually toward perpendicular direction as the film thickness increases. Reported here is a novel way to solve this problem. That is to laminate the Co-based hard magnet films with thin soft magnetic films. The effects of soft film underlayer and lamination, on the magnetic properties of CoPt films has been studied and reported here. Three types of soft magnetic material NiFe, NiFeRe and FeAlSi were chosen to conduct the experiments. Amorphous thin soft sendust film was found to meet the goal. It is found that there was a dramatic improvement of the in-plane loop squareness by inserting a 100 /spl Aring/ amorphous FeAlSi film into the 1200 /spl Aring/ CoPt film. The squareness (S) and the remnant magnetization thickness product (MrT) of the CoPt film (1200 /spl Aring/) without soft FeAlSi film lamination are 0.27 and 3.0 memu/cm/sup 2/, respectively, while the S and the MrT of the CoPt film (1200 /spl Aring/) with soft FeAlSi lamination are 0.60 and 6.32 memu/cm/sup 2/, respectively. Multi-lamination is possible if thick CoPt film is required in applications.

Thin Soft Sendust Film Laminated Copt Hard Films

289 rough interface and thus an effective unpinning on this interface, unpinning which can induce an interface mode. Generalizations to spin waves in multilayers with both types of roughness are also studied and discussed. D. Mercier and J.-C.S. Levy, J. Mag. & Mag. Mat. 369, 360 (1996). FS-13. THIN SOFT SENDUST FILM LAMINATED COR HARD FILMS. S. S. Xue, J. F. Dolejsi, and P. J. Ryan (Seagate Technol., 7801 Comput. Ave. South, M/S NRE240, Minneapolis, Minnesota MN 55435) For most of the CO-based permanent magnet materials. the c-axis tends to grow gradually toward perpendicular direction as the film thickness increase. The in-plane loop squareness of Copt films decreases very quickly as the film thickness increase. Some applications require relatively thick CoPt with large in-plane squareness. The nature of CO-based alloy film obviously contradicts the practical requirements. Reported here is a novel way to solve this problem. That is to laminate the Co-based hard magnet films with thin soft magnetic films(SoftFi1m). The samples were of general structure CoWSoftFilm(tl)/CoWSoftFilm(t2)/Al~03/AITiC Substrate, where tl and t2 were varied from 0 to 300 angstrom. The remanent magnetization thickness product (MrT) and the remanent coercivity (Hcr) of the film stack were measured with a remanent moment magnetometer (RMM). The in-plane hysteresis loop squareness (S) of CoPt films was determined with a magneto-optic magnetometer (MOM). Structural information was analyzed using X-ray diffraction (XRD). The effects of SoftFilm lamination, on the magnetic properties of CoPt films has been studied as a function of t l and t2 thickness and three types of soft magnetic material NiFe, NiFeRe and FeAlSi were chosen to conduct the experiments. From microstructural point of view this thin soft film should be able to disconnect the coherent crystal growth of the succeeding CoPt film and also function as a new seedlayer for the succeeding COR film on top of it. Magnetically the total multilayer functions as a single layer with high in-plane squareness and high MrT. Amorphous thin soft sendust film was found to meet the goal. The MOM looper clearly show that there was a dramatical improvement of the in-plane loop squareness by inserting a IOOA amorphous sendust film into the 1200A CoPt film. The squareness and MrT of the COR film (1200A) without soft sendust lamination is 0.27 and 3.0 memu/cm, respectively, while the squareness and MrT of the COR film (1200A) with soft sendust lamination is 0.60 and 6.32 memul cm, respectively. Multi-lamination is possible if thick CoPt film is required in applications.