Thickness and Growth Temperature Dependence of Structure and Magnetism in FePt Thin Films
We describe structural and magnetic measurements of polycrystalline, L1{sub 0} chemical-ordered Fe(55-60)Pt(45-40) films as a function of film thickness (from 3 to 13 nm) and growth temperature (270-370 C). With increasing film thickness, the coercivity increases from about 1 kOe up to 11 kOe (growth at 400 C), while for increasing growth temperature, the coercivity grows from 0.2 to 6 kOe for 4.3 nm thick films and 1.6 to 10 kOe for 8.5 nm thick films. There is a strong, nearly linear correlation between coercivity and the extent of L1{sub 0} chemical order. In all the films there is a mixture of L1{sub 0} and chemically disordered, fcc phases. The grain size in the L1{sub 0} phase increases with both film thickness and growth temperature (increasing chemical order), while in the fcc phase the grain size remains nearly constant and is smaller than in the L1{sub 0} phase. The films all contain twins and stacking faults. The relationship between the coercivity and the film structure is discussed and we give a possible mechanism for the lack of chemical order in the very thin films (lack of nucleation sites for the L1{sub 0} phase).
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 813258
- Report Number(s):
- SLAC-PUB-9988; TRN: US200316%%22
- Resource Relation:
- Other Information: PBD: 17 Jun 2003
- Country of Publication:
- United States
- Language:
- English
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