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Title: Manipulation of competing ferromagnetic and antiferromagnetic domains in exchange-biased nanostructures

In this work, using photoemission electron microscopy combined with x-ray magnetic circular dichroism we show that a progressive spatial confinement of a ferromagnet (FM), either through thickness variation or laterally via patterning, actively controls the domains of uncompensated spins in the antiferromagnet (AF) in exchange-biased systems. Direct observations of the spin structure in both sides of the FM/AF interface in a model system, Ni/FeF2, show that the spin structure is determined by the balance between the competing FM and AF magnetic energies. Coexistence of exchange bias domains, with opposite directions, can be established in Ni/FeF2 bilayers for Ni thicknesses below 10 nm. Patterning the Ni/FeF2 heterostructures with antidots destabilizes the FM state, enhancing the formation of opposite exchange bias domains below a critical antidot separation of the order of a few FeF2 crystal domains. The results suggest that dimensional confinement of the FM may be used to manipulate the AF spin structure in spintronic devices and ultrahigh-density information storage media. Lastly, the underlying mechanism of the uncompensated AF domain formation in Ni/FeF2 may be generic to other magnetic systems with complex noncollinear FM/AF spin structures.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [5] ;  [6] ;  [6] ;  [2] ;  [1] ;  [1]
  1. Universitat de Barcelona (Spain). Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB)
  2. University of California San Diego, La Jolla, CA (United States). Department of Physics and Center for Advanced Nanoscience
  3. University of the Basque Country, Leioa (Spain). Department of Chemical-Physics, BCMaterials; IKERBASQUE, Basque Foundation for Science (Spain)
  4. Institut de Microelectronica de Barcelona (Spain)
  5. Institut Catala de Nanociència i Nanotecnologia (Spain)
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
Publication Date:
Grant/Contract Number:
AC02-05CH11231; FG02-87ER45332; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 17; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1378656
Alternate Identifier(s):
OSTI ID: 1378656