Effects of the Cu Doping on Critical Behavior of La0.7Ca0.3MnO3

We have studied the influence of the Cu-doping on the critical properties of a polycrystalline sample of La0.7Ca0.3Mn0.95Cu0.05O3 prepared by solid-state reaction. Analyses of static magnetization data in the vicinity of the ferromagnetic-paramagnetic phase transition based on the modified Arrott plot reveal critical parameters of T-C approximate to 197.3 K , beta = 0.49 +/- 0.03 and gamma = 1.04 +/- 0.04. These parameters are in good agreement with a magnetic equation of state M(H, epsilon) = epsilon(beta)f(+/-)(H/epsilon(beta+gamma)), where epsilon = (T - T-C)/T-C (the reduced temperature), f(+) for T > T-C and f(-) for T < T-C. Comparing with theoretical models, the critical exponents in our case are close to those expected for the mean-field theory. This reflects that the Cu doping leads to the second-order phase transition in La(0.7)Ca(0.3)Mn(0.95)Cu(0.05)O3 while the parent compound of La0.7Ca0.3MnO exhibits the first-order phase transition. Such the phenomenon is assigned to changes in structural parameters, Mn3+/Mn4+ ratio, and magnetic interaction mechanisms caused by Cu dopants.

Title:

Effects of the Cu Doping on Critical Behavior of La0.7Ca0.3MnO3
Authors: Phan, T. L.
Thanh, P. Q.
Sinh, N. H
Keywords: Critical behavior
magnetic phase transition
perovskite manganites
TRANSPORT-PROPERTIES
CRITICAL EXPONENTS
PHASE-TRANSITION
Issue Date: 2012
Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Citation: ISIKNOWLEDGE
Abstract: We have studied the influence of the Cu-doping on the critical properties of a polycrystalline sample of La0.7Ca0.3Mn0.95Cu0.05O3 prepared by solid-state reaction. Analyses of static magnetization data in the vicinity of the ferromagnetic-paramagnetic phase transition based on the modified Arrott plot reveal critical parameters of T-C approximate to 197.3 K , beta = 0.49 +/- 0.03 and gamma = 1.04 +/- 0.04. These parameters are in good agreement with a magnetic equation of state M(H, epsilon) = epsilon(beta)f(+/-)(H/epsilon(beta+gamma)), where epsilon = (T - T-C)/T-C (the reduced temperature), f(+) for T > T-C and f(-) for T < T-C. Comparing with theoretical models, the critical exponents in our case are close to those expected for the mean-field theory. This reflects that the Cu doping leads to the second-order phase transition in La(0.7)Ca(0.3)Mn(0.95)Cu(0.05)O3 while the parent compound of La0.7Ca0.3MnO exhibits the first-order phase transition. Such the phenomenon is assigned to changes in structural parameters, Mn3+/Mn4+ ratio, and magnetic interaction mechanisms caused by Cu dopants.
Description: TNS06897 ; IEEE TRANSACTIONS ON MAGNETICS Volume: 48 Issue: 4 Pages: 1293-1296 Published: APR 2012
URI: http://repository.vnu.edu.vn/handle/VNU_123/27339
ISSN: 0018-9464
Appears in Collections:Bài báo của ĐHQGHN trong Web of Science

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