Structure and magnetic properties of sputtered thin films of Fe[sub 0. 79]Ge[sub 0. 21]

Journal Article · Fri Oct 15 04:00:00 EDT 1993 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.354298· OSTI ID:6255556

Hamdeh, H H ^[1]; Oliver, S A ^[2]; Fultz, B; Gao, Z Q ^[3]

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1. Department of Physics, Wichita State University, Wichita, Kansas 67260 (United States)
2. Center for Electromagnetics Research, Northeastern University, Boston, Massachusetts 02115 (United States)
3. Mail 138-78, California Institute of Technology, Pasadena, California 91125 (United States)

Films of Fe[sub 0.79]Ge[sub 0.21] with thicknesses of 300 nm were synthesized by ion beam sputtering, and were annealed at temperatures from 200 to 550 [degree]C. The materials were characterized by x-ray diffractometry, Moessbauer spectrometry, vibrating sample magnetometry, ferromagnetic resonance spectrometry, and electrical resistivity measurements. The as-prepared materials comprised chemically disordered bcc crystallites of sizes less than 20 nm, and were found to have a distribution of internal strains. Upon annealing at temperatures of 250 [degree]C and below, there occurred strain relaxation, some evolution of short range chemical order, and an improvement in soft magnetic properties. The coercive field was a minimum for the sample annealed at 250 [degree]C. Crystallite growth occurred at higher annealing temperatures, accompanied by a transition in several measured parameters from those of ultrafine grained materials to those typical of polycrystalline materials. This trend can be explained with the random anisotropy model. Moessbauer and magnetization measurements indicated that the Ge atoms behave as magnetic holes. The [sup 57]Fe hyperfine magnetic field distribution, and its change during chemical ordering, can be calculated approximately with a model of magnetic response. The large local isomer shifts at [sup 57]Fe atoms near Ge atoms suggest that a local depletion of 4[ital s] conduction electron density should be incorporated into the model.

• DOE Contract Number: FG03-86ER45270
• OSTI ID: 6255556
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 74:8; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOY SYSTEMS
ALLOYS
ANNEALING
BINARY ALLOY SYSTEMS
COHERENT SCATTERING
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
GERMANIUM ALLOYS
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MAGNETIC PROPERTIES
MICROSTRUCTURE
MOESSBAUER EFFECT
PHYSICAL PROPERTIES
SCATTERING
SPUTTERING
THIN FILMS
X-RAY DIFFRACTION