Evidence for Jahn-Teller polaron formation and spin-cluster-assisted variable-range-hopping conduction in La0.7Ca0.3MnO3

被引：62
作者：
Kumar, PSA
Joy, PA [1 ]
Date, SK
机构：
[1] Natl Chem Lab, Phys & Mat Chem Div, Poona 411008, Maharashtra, India
[2] Univ Poona, Dept Phys, Ctr Adv Studies Mat Sci & Solid State Phys, Poona 411007, Maharashtra, India
来源：
JOURNAL OF PHYSICS-CONDENSED MATTER | 1998年 / 10卷 / 17期
关键词：
D O I：
10.1088/0953-8984/10/17/001
中图分类号：
O469 [凝聚态物理学];
学科分类号：
070205 ;
摘要：
Resistivity (15-710 K), magnetization (80-723 K), and calorimetric (200-623 K) measurements on La0.7Ca0.3MnO3 have shown evidence for the formation of Jahn-Teller (JT) polarons below similar to 545 K. Above 560 K, activated conduction with E-a = 0.05 eV is observed and chi(-1)(T) shows Curie-Weiss behaviour. Over the temperature range 270-340 K, the conductivity follows Mott's VRH model and chi(-1)(T) provides evidence of the formation of spin clusters. Calorimetric study shows phase transitions at T-c (=245 K), 345 K and 545 K. The role of the JT polaron in determining the electronic and magnetic properties above T-c is discussed.
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页码：L269 / L275
页数：7
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