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Title: Origin of spin-glass and exchange bias in La{sub 1∕3}Sr{sub 2∕3}FeO{sub 3−γ} nanoparticles

The structure and the magnetic properties of nanopowdered samples of La{sub 1∕3}Sr{sub 2∕3}FeO{sub 3−γ} with average particles size d in the range of 67-367 nm prepared by a sol-gel method were investigated in detail. The samples were characterized by X-ray diffraction, scanning electron microscopy, specific heat, Mössbauer spectroscopy, ac susceptibility, and magnetization measurements. Exchange bias with vertical magnetization shift was found in all samples. Charge ordering and antiferromagnetism were observed close to 200 K for large particles (d ≥ 304 nm) samples, while for particles with intermediated and smaller values (d ≤ 156 nm) a cluster-glass like behaviour and a short range charge ordering were seen near 115 K and 200 K, respectively. The spin-glass like and exchange bias behaviour in nanopowdered samples of La{sub 1∕3}Sr{sub 2∕3}FeO{sub 3−γ} are associated to compact Fe{sup 3+} antiferromagnetic (AF) clusters caused by an oxygen deficiency, which was found to be higher in the samples with the smallest average particles sizes. The effect of exchange bias and vertical magnetization shifts are explained by a simple model involving the interaction of one AF phase with a canted AF phase.
Authors:
;  [1] ;  [2] ;  [3]
  1. Departamento de Física Teórica e Experimental, UFRN, Natal (Brazil)
  2. Departamento de Física, UERN, Mossoró, RN (Brazil)
  3. Departamento de Física, UFPE, Recife, PE (Brazil)
Publication Date:
OSTI Identifier:
22271214
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION SPECTROSCOPY; ANTIFERROMAGNETISM; FERRITES; LANTHANUM COMPOUNDS; MAGNETIC SUSCEPTIBILITY; MAGNETIZATION; MOESSBAUER EFFECT; NANOSTRUCTURES; PARTICLE SIZE; PARTICLES; POWDERS; SCANNING ELECTRON MICROSCOPY; SOL-GEL PROCESS; SPECIFIC HEAT; SPIN GLASS STATE; STRONTIUM COMPOUNDS; X-RAY DIFFRACTION