Boltzmann-equation approach to the negative magnetoresistance of ferromagnetic--normal-metal multilayers

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.8287· OSTI ID:6986983

Hood, R Q; Falicov, L M ^[1]

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1. Department of Physics, University of California, Berkeley, California 94720 (United States) Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

The Boltzmann equation is solved for a system consisting of a ferromagnetic--normal-metal--ferromagnetic metallic trilayer. The in-plane conductance of the film is calculated for two configurations: the ferromagnetic layers aligned (i) parallel and (ii) antiparallel to each other. The results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by application of an external magnetic field. The calculation depends on (a) geometric parameters (the thicknesses of the layers), (b) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in the layers), (c) bulk sample properties (conductivity relaxation times), (d) interface scattering properties (diffuse scattering versus potential scattering at the interfaces), and (e) outer surface scattering properties (specular versus diffuse surface scattering). For perfect specular scattering at the surfaces the problem becomes identical to an infinite multilayer, periodic system. It is found that a large negative magnetoresistance requires, in general, considerable asymmetry in the interface scattering for the two spin orientations. All qualitative features of the experiments are reproduced. Quantitative agreement can be achieved with sensible values of the parameters. The effect can be conceptually explained based on considerations of phase-space availability for an electron of a given spin orientation as it travels through the multilayer sample in the various configurations.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6986983
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 46:13; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FERROMAGNETIC MATERIALS
MAGNETORESISTANCE
LAYERS
METALS
BOLTZMANN EQUATION
EFFECTIVE MASS
FILMS
MAGNETIZATION
SUPERLATTICES
DIFFERENTIAL EQUATIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EQUATIONS
MAGNETIC MATERIALS
MASS
MATERIALS
PARTIAL DIFFERENTIAL EQUATIONS
PHYSICAL PROPERTIES
360104* - Metals & Alloys- Physical Properties