Dipolar mechanisms for magnetic anisotropy in amorphous ferrimagnetic alloys

Journal Article · Wed Mar 01 00:00:00 EST 1978 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.324857· OSTI ID:5122792

Cargill, III, G S; Mizoguchi, T

Classical magnetic dipolar interactions can make significant contributions to magnetic anisotropy in amorphous ferrimagnetic alloys with slight structural anisotropies on either atomic or microstructural scales. Simple expressions have been derived for this magnetic anisotropy in terms of structural anisotropy parameters, p, V, and ..delta..x. For an alloy with atomic scale structural anisotropy (pair ordering), p is a measure of alignment of unlike nearest neighbor pairs. For an alloy with aligned, elongated composition inhomogeneities, V is the volume fraction of the inhomogeneities and ..delta..x is the composition difference (atom fraction) between the inhomogeneities and their surroundings. Accounting for magnetic anisotropy observed experimentally in bias-sputtered GdCo-based alloy films solely in terms of pair ordering and classical dipolar interactions requires papprox.0.015. Accounting for the anisotropy solely in terms of composition inhomogeneities requires Vapprox.0.5 and ..delta..xapprox.0.1. Although such atomic scale structural anisotropy will be very difficult to detect with currently available experimental techniques, composition inhomogeneities of this magnitude should be easily detectible in x-ray, electron, or neutron small-angle scattering experiments. No evidence for anisotropic composition inhomogeneities is seen in x-ray scattering experiments on micron-thick bias sputtered GdCo-based alloy films, although such inhomogeneities may be present in oxygen-doped, evaporated Gd-Co films and in some annealed Gd-Co films prepared by evaporation and by zero-bias sputtering. Magnetic anisotropy in GdCo-based films probably involves spin orbit interactions as well as classical magnetic dipolar interactions.

• Research Organization: IBM Research Center, Yorktown Heights, New York 10598
• OSTI ID: 5122792
• Journal Information: J. Appl. Phys.; (United States), Vol. 49:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT BASE ALLOYS
MAGNETIC PROPERTIES
GADOLINIUM ALLOYS
AMORPHOUS STATE
ANISOTROPY
BINARY ALLOY SYSTEMS
CHEMICAL COMPOSITION
EXCHANGE INTERACTIONS
FERRIMAGNETISM
FILMS
MAGNETIZATION
SPUTTERING
ALLOY SYSTEMS
ALLOYS
COBALT ALLOYS
INTERACTIONS
MAGNETISM
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
360104* - Metals & Alloys- Physical Properties