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Title: Effect of oxygen content on transport and magnetic properties of PrBaCo{sub 2}O{sub 5.50+δ}

Samples of PrBaCo{sub 2}O{sub 5.50+δ} (δ = −0.15–0.14), synthesized by solid-state reactions, were investigated to ascertain oxygen compositional effects on transport/magnetic properties. Resistivity decreases with increasing oxygen content, indicative of p-type conduction. A metal-insulator transition was observed at 330 K only for sample PrBaCo{sub 2}O{sub 5.52}, coinciding with phase transition and spin-state transition of Co{sup 3+}. When δ deviates from zero, samples show insulator–insulator transitions, although for sample δ = 0.14, no transition occurs but only semi-conductive behavior appears. Electronic transport is governed by the hopping mechanism at lower temperatures and thermal activation at higher temperatures. All samples underwent paramagnetic–ferromagnetic–antiferromagnetic transitions, except PrBaCo{sub 2}O{sub 5.64}, which only went through a paramagnetic–ferromagnetic transition. The ferromagnetic state for δ < 0 originates with the Co{sup 3+}/Co{sup 2+} super-exchange interaction; for δ > 0, it stems from the Co{sup 3+}/Co{sup 4+} double exchange interaction.
Authors:
; ; ; ;  [1] ;  [2] ;  [2] ;  [1]
  1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)
  2. School of Physics, Peking University, Beijing 100871 (China)
Publication Date:
OSTI Identifier:
22475760
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 65; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIFERROMAGNETISM; BARIUM COMPOUNDS; COBALT COMPOUNDS; ELECTRICAL PROPERTIES; EXCHANGE INTERACTIONS; MAGNETIC PROPERTIES; OXYGEN COMPOUNDS; PARAMAGNETISM; PHASE TRANSFORMATIONS; PRASEODYMIUM COMPOUNDS; SOLIDS; X-RAY DIFFRACTION