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Title: Role of diffused Co atoms in improving effective exchange coupling in Sm-Co/Fe spring magnets.

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); ONR
OSTI Identifier:
914879
Report Number(s):
ANL/MSD/JA-57938
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US200812%%125
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. B; Journal Volume: 75; Journal Issue: Mar. 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; MAGNETS; SAMARIUM ALLOYS; COBALT ALLOYS; IRON; COUPLING

Citation Formats

Choi, Y., Jiang, J. S., Ding, Y., Rosenberg, R. A., Pearson, J. E., Bader, S. D., Zambano, A., Murakami, M., Takeuchi, I., Wang, Z. L., Liu, J. P., Materials Science Division, Univ. of Texas, Georgia Inst. Tech., and Univ. of Maryland. Role of diffused Co atoms in improving effective exchange coupling in Sm-Co/Fe spring magnets.. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.75.104432.
Choi, Y., Jiang, J. S., Ding, Y., Rosenberg, R. A., Pearson, J. E., Bader, S. D., Zambano, A., Murakami, M., Takeuchi, I., Wang, Z. L., Liu, J. P., Materials Science Division, Univ. of Texas, Georgia Inst. Tech., & Univ. of Maryland. Role of diffused Co atoms in improving effective exchange coupling in Sm-Co/Fe spring magnets.. United States. doi:10.1103/PhysRevB.75.104432.
Choi, Y., Jiang, J. S., Ding, Y., Rosenberg, R. A., Pearson, J. E., Bader, S. D., Zambano, A., Murakami, M., Takeuchi, I., Wang, Z. L., Liu, J. P., Materials Science Division, Univ. of Texas, Georgia Inst. Tech., and Univ. of Maryland. Thu . "Role of diffused Co atoms in improving effective exchange coupling in Sm-Co/Fe spring magnets.". United States. doi:10.1103/PhysRevB.75.104432.
@article{osti_914879,
title = {Role of diffused Co atoms in improving effective exchange coupling in Sm-Co/Fe spring magnets.},
author = {Choi, Y. and Jiang, J. S. and Ding, Y. and Rosenberg, R. A. and Pearson, J. E. and Bader, S. D. and Zambano, A. and Murakami, M. and Takeuchi, I. and Wang, Z. L. and Liu, J. P. and Materials Science Division and Univ. of Texas and Georgia Inst. Tech. and Univ. of Maryland},
abstractNote = {No abstract prepared.},
doi = {10.1103/PhysRevB.75.104432},
journal = {Phys. Rev. B},
number = Mar. 2007,
volume = 75,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • No abstract prepared.
  • No abstract prepared.
  • Magnetization reversal in nanoscale (Sm-Co)/Fe (hard/soft) bilayer exchange-spring magnets with in-plane uniaxial magnetic anisotropy was investigated by magnetometry, conversion-electron Moessbauer spectroscopy (CEMS) and atomistic Fe spin-structure calculations. Magnetization loops along the easy direction exhibit signatures typical of exchange-spring magnets. In-field CEMS at inclined {gamma}-ray incidence onto thin (2 nm) {sup 57}Fe probe layers embedded at various depths in the 20-nm-thick natural (soft) Fe layer provides depth-dependent information (via the line-intensity ratio R{sub 23} as a function of the applied field H) about the in-plane rotation of Fe spins. A minimum in the R{sub 23}-vs-H dependence at (H{sub min}, R{sub min})more » determines the field where Fe magnetic moments roughly adopt an average perpendicular orientation during their reversal from positive to negative easy-axis orientation. A monotonic decrease of H{sub min} with distance from the hard/soft interface is observed. Rotation of Fe spins takes place even in the interface region in applied fields far below the field of irreversible switching, H{sub irr}, of the hard phase. Formation of an Fe-Co alloy is detected in the interface region. For comparison, the noncollinear Fe spin structure during reversal and the resulting R{sub 23} ratio were obtained by electronic-structure calculations based on a quantum-mechanical Hamiltonian for itinerant electrons. The coupling at the hard/soft interface is described by the uniaxial exchange-anisotropy field, hint, as a parameter. Our calculated R{sub 23} ratios as a function of the (reduced) applied field h exhibit similar features as observed in the experiment, in particular a minimum at (h{sub min}, R{sub min}). R{sub min} is found to increase with hint, thus providing a measure of the interface coupling. Evidence is provided for the existence of fluctuations of the interface coupling. The calculations also show that the Fe spin spiral formed during reversal is highly inhomogeneous. In general, our simulation of the Fe spin structure is applicable for the interpretation of experimental results on layered exchange-spring magnets.« less
  • The depth profile of the intrinsic magnetic properties in an Fe/Sm-Co bilayer fabricated under nearly optimal spring-magnet conditions was determined by complementary studies of polarized neutron reflectometry and micromagnetic simulations. We found that at the Fe/Sm-Co interface, the magnetic properties change gradually at the length scale of 8 nm. In this intermixed interfacial region, the saturation magnetization and magnetic anisotropy are lower and the exchange stiffness is higher than values estimated from the model based on a mixture of Fe and Sm-Co phases. Therefore, the intermixed interface yields superior exchange coupling between the Fe and Sm-Co layers, but at themore » cost of average magnetization.« less