Giant magnetoresistance at low fields in [(Ni[sub [ital x]]Fe[sub 1[minus]][sub [ital x]])[sub [ital y]]Ag[sub 1[minus]][sub [ital y]]]/Ag multilayers prepared by molecular beam epitaxy (abstract)

Journal Article · Tue Nov 15 00:00:00 EST 1994 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.358181· OSTI ID:6909786

Farrow, R F.C.; Marks, R F; Cebollada, A; Toney, M F; Dobbertin, D; Beyers, R; Parkin, S S.P. ^[1]; Rabedeau, T A ^[2]

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1. IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099 (United States)
2. Stanford Synchrotron Radiation Laboratory, Stanford, California 94305 (United States)

The structural changes that accompany the development of GMR (giant magnetoresistance) at low ([approx lt]10 Oe) fields in annealed magnetic multilayers are of current interest because of potential applications of such structures in sensors. In this paper we report a study of the development of GMR in [111]-oriented multilayers comprising ferromagnetic films of a mixture of Ag and permalloy (Ni[sub [ital x]]Fe[sub 1[minus][ital x]], [ital x][similar to]0.8) alternating with Ag spacer films. The multilayers were grown by molecular beam epitaxy (MBE) on Pt(111) seed films on sapphire (0001) substrates at temperatures in the range 20 to 200 [degree]C. The structure of the multilayers was investigated using x-ray diffraction and electron microscopy. For a series of multilayers grown with nominally identical ferromagnetic and spacer layer thicknesses, the magnetoresistance is found to be strongly dependent on both growth temperature and subsequent annealing temperature. The multilayers exhibited a negative magnetoresistance in the as-grown state which more than doubled when the growth temperature was increased from 20 to 100 [degree]C. However, the highest magnetoresistance (peak 5.6%; maximum slope 0.4% per Oe) was obtained by annealing (at 400 [degree]C) multilayers grown at 100 [degree]C. Transmission electron microscopy studies of such multilayers showed no evidence for discontinuities or penetration of the ferromagnetic films by Ag along grain boundaries. Thus, we conclude that discontinuous or granular multilayers with complete phase separation are not necessary for GMR with low saturation fields.

• OSTI ID: 6909786
• Journal Information: Journal of Applied Physics; (United States), Vol. 76:10; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON ALLOYS
MAGNETORESISTANCE
NICKEL ALLOYS
SILVER
SILVER ALLOYS
ANNEALING
LAYERS
MICROSTRUCTURE
MOLECULAR BEAM EPITAXY
PHASE STUDIES
TERNARY ALLOY SYSTEMS
ALLOY SYSTEMS
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EPITAXY
HEAT TREATMENTS
METALS
PHYSICAL PROPERTIES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties