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Title: Rhombohedral magnetostriction in dilute iron (Co) alloys

Abstract

Iron is a well-utilized material in structural and magnetic applications. This does not mean, however, that it is well understood, especially in the field of magnetostriction. In particular, the rhombohedral magnetostriction of iron, λ{sub 111}, is anomalous in two respects: it is negative in sign, in disagreement with the prediction of first principles theory, and its magnitude decreases with increasing temperature much too rapidly to be explained by a power law dependence on magnetization. These behaviors could arise from the location of the Fermi level, which leaves a small region of the majority 3d t{sub 2g} states unfilled, possibly favoring small internal displacements that split these states. If this view is correct, adding small amounts of Co to Fe fills some of these states, and the value of λ{sub 111} should increase toward a positive value, as predicted for perfect bcc Fe. We have measured the magnetostriction coefficients (λ{sub 111} and λ{sub 100}) of pure Fe, Fe{sub 97}Co{sub 3}, and Fe{sub 94}Co{sub 6} single crystals from 77 K to 450 K. Resonant ultrasound spectroscopy has been used to check for anomalies in the associated elastic constants, c{sub 44} and c′. The additional electrons provided by the cobalt atoms indeed produced positive contributionsmore » to both magnetostriction constants, λ{sub 111} and λ{sub 100}, exhibiting an increase of 2.8 × 10{sup −6} per at. % Co for λ{sub 111} and 3.8 × 10{sup −6} per at. % Co for λ{sub 100}.« less

Authors:
; ;  [1];  [2];  [3];  [4];  [5];  [5];  [6]
  1. Metallurgy and Fasteners Branch, Naval Surface Warfare Center, Carderock Division, Bethesda, Maryland 20817 (United States)
  2. Physics Department, University of Louisiana at Lafayette, Lafayette, Louisiana 70504 (United States)
  3. Clark Associates, Adelphi, Maryland 20783 (United States)
  4. Spectrum Technology Group, Inc., Gaithersburg, Maryland 20877 (United States)
  5. Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States)
  6. (United States)
Publication Date:
OSTI Identifier:
22409937
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BCC LATTICES; COBALT; ELASTICITY; FERMI LEVEL; G STATES; INTERMETALLIC COMPOUNDS; IRON; MAGNETIZATION; MAGNETOSTRICTION; MONOCRYSTALS; TEMPERATURE DEPENDENCE; TRIGONAL LATTICES

Citation Formats

Jones, Nicholas J., E-mail: nicholas.j.jones1@navy.mil, Wun-Fogle, Marilyn, Restorff, J. B., Petculescu, Gabriela, Clark, Arthur E., Hathaway, Kristl B., Schlagel, Deborah, Lograsso, Thomas A., and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011. Rhombohedral magnetostriction in dilute iron (Co) alloys. United States: N. p., 2015. Web. doi:10.1063/1.4916541.
Jones, Nicholas J., E-mail: nicholas.j.jones1@navy.mil, Wun-Fogle, Marilyn, Restorff, J. B., Petculescu, Gabriela, Clark, Arthur E., Hathaway, Kristl B., Schlagel, Deborah, Lograsso, Thomas A., & Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011. Rhombohedral magnetostriction in dilute iron (Co) alloys. United States. doi:10.1063/1.4916541.
Jones, Nicholas J., E-mail: nicholas.j.jones1@navy.mil, Wun-Fogle, Marilyn, Restorff, J. B., Petculescu, Gabriela, Clark, Arthur E., Hathaway, Kristl B., Schlagel, Deborah, Lograsso, Thomas A., and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011. Thu . "Rhombohedral magnetostriction in dilute iron (Co) alloys". United States. doi:10.1063/1.4916541.
@article{osti_22409937,
title = {Rhombohedral magnetostriction in dilute iron (Co) alloys},
author = {Jones, Nicholas J., E-mail: nicholas.j.jones1@navy.mil and Wun-Fogle, Marilyn and Restorff, J. B. and Petculescu, Gabriela and Clark, Arthur E. and Hathaway, Kristl B. and Schlagel, Deborah and Lograsso, Thomas A. and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011},
abstractNote = {Iron is a well-utilized material in structural and magnetic applications. This does not mean, however, that it is well understood, especially in the field of magnetostriction. In particular, the rhombohedral magnetostriction of iron, λ{sub 111}, is anomalous in two respects: it is negative in sign, in disagreement with the prediction of first principles theory, and its magnitude decreases with increasing temperature much too rapidly to be explained by a power law dependence on magnetization. These behaviors could arise from the location of the Fermi level, which leaves a small region of the majority 3d t{sub 2g} states unfilled, possibly favoring small internal displacements that split these states. If this view is correct, adding small amounts of Co to Fe fills some of these states, and the value of λ{sub 111} should increase toward a positive value, as predicted for perfect bcc Fe. We have measured the magnetostriction coefficients (λ{sub 111} and λ{sub 100}) of pure Fe, Fe{sub 97}Co{sub 3}, and Fe{sub 94}Co{sub 6} single crystals from 77 K to 450 K. Resonant ultrasound spectroscopy has been used to check for anomalies in the associated elastic constants, c{sub 44} and c′. The additional electrons provided by the cobalt atoms indeed produced positive contributions to both magnetostriction constants, λ{sub 111} and λ{sub 100}, exhibiting an increase of 2.8 × 10{sup −6} per at. % Co for λ{sub 111} and 3.8 × 10{sup −6} per at. % Co for λ{sub 100}.},
doi = {10.1063/1.4916541},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}