Growth induced magnetic anisotropy in amorphous thin films. Annual progress report year 1, November 4, 1994--October 31, 1995

Technical Report · Sat Jul 01 04:00:00 EDT 1995

DOI:https://doi.org/10.2172/86991· OSTI ID:86991

Hellman, F ^[1]

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1. Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Physics

The work in the past year has primarily involved three areas of magnetic thin films: amorphous rare earth-transition metal alloys, epitaxial COPt3 thin films, and exchange coupled antiferromagnetic insulators. In the amorphous alloys, the authors have focused on understanding the cause and the effect of the growth-surface-induced perpendicular magnetic anisotropy. Using the results of previous work, they are able to control this anisotropy quite precisely. This anisotropy is predicted to have dramatic and as-yet unobserved effects on the underlying nature of the magnetism. The work on the epitaxial Co-Pt alloys was originally undertaken as a comparison study to the amorphous alloys. The authors have discovered that these alloys exhibit a remarkable new phenomena; a surface-induced miscibility gap in a material which is believed to be completely miscible in the bulk. This miscibility gap is 100% correlated with the perpendicular anisotropy, although the connection is not yet clear, and is presumably linked to a magnetic energy of mixing which tends to drive a material towards clustering. The problem of exchange coupling in multilayers impacts many of the current research areas in magnetism. NiO/CoO multilayers can be prepared with coherent interfaces. The specific heat shows unambiguously the ordering of the spins in the layers. The results show clearly the transition from a single transition temperature to two distinct transitions with increasing thickness of the individual layers. From this data, the authors are able to determine the interface magnetic exchange coupling constant and the effect on the transition temperature of finite layer thickness.

• Research Organization: California Univ., San Diego, La Jolla, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG03-95ER45529
• OSTI ID: 86991
• Report Number(s): DOE/ER--45529; CONF-950380--2; ON: DE95015362
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
ANISOTROPY
ANTIFERROMAGNETIC MATERIALS
COBALT ALLOYS
COBALT OXIDES
MAGNETIC PROPERTIES
NICKEL OXIDES
PHASE TRANSFORMATIONS
PLATINUM ALLOYS
PROGRESS REPORT
RARE EARTH ALLOYS
SCATTERING
TRANSITION ELEMENT ALLOYS