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Title: Magnetoresistive detection of strongly pinned uncompensated magnetization in antiferromagnetic FeMn

Abstract

Here we observed and studied pinned uncompensated magnetization in an antiferromagnet using magnetoresistance measurements. For this, we developed antiferromagnet-ferromagnet spin valves (AFSVs) that consist of an antiferromagnetic layer and a ferromagnetic one, separated by a nonmagnetic conducting spacer. In an AFSV, the uncompensated magnetization in the antiferromagnet affects scattering of spin-polarized electrons giving rise to giant magnetoresitance (GMR). By measuring angular dependence of AFSVs' resistance, we detected pinned uncompensated magnetization responsible for the exchange bias effect in an antiferromagnet- only exchange bias system Cu/FeMn/Cu. The fact that GMR measured in this system persists up to 110 kOe indicates that the scattering occurs on strongly pinned uncompensated magnetic moments in FeMn. This strong pinning can be explained if this pinned uncompensated magnetization is a thermodynamically stable state and coupled to the antiferromagnetic order parameter. Finally, using the AFSV technique, we confirmed that the two interfaces between FeMn and Cu are magnetically different: The uncompensated magnetization is pinned only at the interface with the bottom Cu layer.

Authors:
 [1];  [2];  [3];  [3];  [3];  [3];  [3]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Texas A&M Univ., College Station, TX (United States). Dept. of Physics and Astronomy
  2. Texas A&M Univ., College Station, TX (United States). Dept. of Physics and Astronomy; Texas A&M Univ., College Station, TX (United States). Dept. of Materials Science and Engineering
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1352609
Alternate Identifier(s):
OSTI ID: 1339766
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Lapa, Pavel N., Roshchin, Igor V., Ding, Junjia, Pearson, John. E., Novosad, Valentine, Jiang, J. S., and Hoffmann, Axel. Magnetoresistive detection of strongly pinned uncompensated magnetization in antiferromagnetic FeMn. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.020409.
Lapa, Pavel N., Roshchin, Igor V., Ding, Junjia, Pearson, John. E., Novosad, Valentine, Jiang, J. S., & Hoffmann, Axel. Magnetoresistive detection of strongly pinned uncompensated magnetization in antiferromagnetic FeMn. United States. doi:10.1103/PhysRevB.95.020409.
Lapa, Pavel N., Roshchin, Igor V., Ding, Junjia, Pearson, John. E., Novosad, Valentine, Jiang, J. S., and Hoffmann, Axel. Tue . "Magnetoresistive detection of strongly pinned uncompensated magnetization in antiferromagnetic FeMn". United States. doi:10.1103/PhysRevB.95.020409. https://www.osti.gov/servlets/purl/1352609.
@article{osti_1352609,
title = {Magnetoresistive detection of strongly pinned uncompensated magnetization in antiferromagnetic FeMn},
author = {Lapa, Pavel N. and Roshchin, Igor V. and Ding, Junjia and Pearson, John. E. and Novosad, Valentine and Jiang, J. S. and Hoffmann, Axel},
abstractNote = {Here we observed and studied pinned uncompensated magnetization in an antiferromagnet using magnetoresistance measurements. For this, we developed antiferromagnet-ferromagnet spin valves (AFSVs) that consist of an antiferromagnetic layer and a ferromagnetic one, separated by a nonmagnetic conducting spacer. In an AFSV, the uncompensated magnetization in the antiferromagnet affects scattering of spin-polarized electrons giving rise to giant magnetoresitance (GMR). By measuring angular dependence of AFSVs' resistance, we detected pinned uncompensated magnetization responsible for the exchange bias effect in an antiferromagnet- only exchange bias system Cu/FeMn/Cu. The fact that GMR measured in this system persists up to 110 kOe indicates that the scattering occurs on strongly pinned uncompensated magnetic moments in FeMn. This strong pinning can be explained if this pinned uncompensated magnetization is a thermodynamically stable state and coupled to the antiferromagnetic order parameter. Finally, using the AFSV technique, we confirmed that the two interfaces between FeMn and Cu are magnetically different: The uncompensated magnetization is pinned only at the interface with the bottom Cu layer.},
doi = {10.1103/PhysRevB.95.020409},
journal = {Physical Review B},
number = 2,
volume = 95,
place = {United States},
year = {Tue Jan 17 00:00:00 EST 2017},
month = {Tue Jan 17 00:00:00 EST 2017}
}

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