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Title: The unusual magnetism of nanoparticle LaCoO3

Bulk and nanoparticle powders of LaCoO3 (LCO) were synthesized and their magnetic and structural properties were studied using SQUID magnetometry and neutron diffraction. The bulk and large nanoparticles exhibit weak ferromagnetism (FM) below T≈85K and a crossover from strong to weak antiferromagnetic (AFM) correlations near a transition expressed in the lattice parameters, To ≈ 40 K. This crossover does not occur in the smallest nanoparticles; instead, the magnetic behavior is predominantly ferromagnetic. The amount of FM in the nanoparticles depends on the amount of Co3O4 impurity phase, which induces tensile strain on the LCO lattice. A core-interface model is introduced, with the core region exhibiting the AFM crossover and with FM in the interface region near surfaces and impurity phases.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Univ. of California, Santa Cruz, CA (United States). Dept. of Physics
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
  5. Univ. of California, Santa Cruz, CA (United States). Dept. of Chemistry
  6. Castilleja School, Palo Alto, CA (United States)
Publication Date:
OSTI Identifier:
1265484
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 27; Journal Issue: 17; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY