Hostname: page-component-848d4c4894-5nwft Total loading time: 0 Render date: 2024-06-05T06:37:17.202Z Has data issue: false hasContentIssue false
  • English
  • Français

Point Defects And The B2 To Fcc Transformation In Milled FeRh

Published online by Cambridge University Press:  10 February 2011

Luke S.-J. Peng  and
Gary S. Collins
Luke S.-J. Peng
Affiliation:
Department of Physics, Washington State University, Pullman, WA 99164
Gary S. Collins
Affiliation:
collins@wsu.edu
Get access

Abstract

Mössbauer measurements were made on FeRh containing 52 atomic percent (at.%) Fe after mechanical milling for different times in a high-energy SPEX 8000 vibrator mill. Hyperfine fields are compared with fields for annealed ferromagnetic (F) samples having the B2 structure in the range 52–58 at.% Fe. For annealed F samples, hyperfine field shifts of -1.66 T and -1.12 T were detected at majority FeFC and minority FeRh probes due to FeRh antisite atoms in, respectively, the first and second atomic shells. Analysis of dipolar fields indicates that the magnetization lies along the <110> direction. The transformation from F B2 phase to a metastable paramagnetic fcc phase was observed that was half complete in 8 minutes. Analysis of spectra for the milled F B2 phase show that a second point defect was produced by milling that induces shifts of +6 T and +8.5 T, respectively, at majority and minority probes. Manyspectra fits were made under different defect models that led to the conclusion that milling produces point defects in the triple-defect configuration: 2 Fe-vacancies and 1 Fe-antisite atom. Defect concentrations were determined and show that the fractional concentration of vacancies on the Fe-sublattice increases linearly with milling time, reaching 3 at.% after 8 minutes, a very large value. The rate of transformation from B2 to fcc phase appears to be independent of the concentrations of point defects in the B2 phase, indicating that the transformation is purely stress-induced, as in a martensite transformation.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 481: Symposium P – Science and Technology of Semiconductor Surface Preparation , 1997 , 631
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Collins, G. S. and Sinha, P., Materials Science Forum 225–227, 275 (1996).Google Scholar
2. Luke Peng, S.-J. and Gary Collins, S., Materials Science Forum 235–238, 535 (1997); see also G.S. Collins and L. S.-J. Peng, Il Nuovo Cimento 18D, 329 (1996).Google Scholar
3. Navarro, E., Yavari, A.R., Hernando, A., Marquina, C. and Ibarra, M.R., Solid State Communications 100, 57 (1996).Google Scholar
4. Shirane, G., Chen, C.W., Flinn, P.A. and Nathans, R., Physical Review 131, 183 (1963); G. Shirane, R. Nathans and C.W. Chen, Physical Review 134, A1547 (1964).Google Scholar
5. See, e.g., Takahashi, M. and Oshima, R., J. Physique IV, C8–491 (1995).Google Scholar
6. Szajek, A. and Morkowski, J.A., Physica B 193, 81 (1994); V.L. Moruzzi and P.M. Marcus, Physical Review B46, 2864 (1992).Google Scholar
7. Small quadrupole splittings and monopole interaction shifts due to defects that were also fitted will be described elsewhere.Google Scholar