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Magnetic Properties and Scaling Behavior in Perovskite–like La0.7(Ba1−xPbx)0.3CoO3 System

Published online by Cambridge University Press:  21 March 2011

Chiung-Hsiung Chen
Affiliation:
Department of Physics, Chung Cheng University, 160 San-Hsing, Ming-Hsiung, Chia-Yi 621, Taiwan
Ting-Sheng Huang
Affiliation:
Department of Physics, Chung Cheng University, 160 San-Hsing, Ming-Hsiung, Chia-Yi 621, Taiwan
Ming-Fong Tai
Affiliation:
Department of Physics, Chung Cheng University, 160 San-Hsing, Ming-Hsiung, Chia-Yi 621, Taiwan
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Abstract

In this study, we used x-ray diffraction patterns and dc magnetic measurements to investigate the crystallographic structure, magnetic properties and scaling behavior of the distorted perovskite La0.7(Ba1−xPbx)0.3CoO3 (0 ≤ x ≤ 0.5) system with a constant ratio of Co4+/Co3+. Samples with x = 0.0 and 0.1 were crystallized in the cubic structure with a ∼ 7.76 Å whereas samples with x ≥ 0.2 were crystallized in an orthorhombic Pbnm space group with ab ∼ 5.50 Å and c ∼ 7.85 Å. For all our samples the spin-glass-like behavior were observed in low temperature and low field ranges. The Pb2+ substitution on Ba2+ site does not significantly affect the ferromagnetic transition temperature TC, but does introduce large variation in the magnetic strength. In both the ferromagnetic and paramagnetic states the minimum values of the average effective moments provided by every Co ion occur at x = 0.3. We also observed the scaling behaviors of magnetic data in all samples. The derived values of the critical exponents (β, γ, δ) were consistent with those predicted by mean field theory and a three-dimensional Heisenberg model.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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