Influence of A-site cation disorder on structural and magnetocaloric properties of Nd_(0.7–x)La_xSr_(0.3)MnO_3(x=0.0, 0.1, 0.2 & 0.3)

作     者：Sudharshan Vadnala Prem Pal Saket Asthana 

作者机构：Department of Physics Indian Institute of Technology Hyderabad 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2015年第33卷第10期

页      面：1072-1080页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：Project partially supported by Defence Research and Development Organization(DRDO) India(ERIP/ER/0900373/M/01/1430) 

主　　题：manganites magnetocaloric effect relative cooling Curie temperature rare earths 

摘      要：In the present research, the influence of A-site ionic size disorder on structural, magnetic and magnetocaloric properties of Ndo.7_xtaxSr0.3MnO3 （for x=0.0, 0.1, 0.2 ＆ 0.3） compounds were investigated. These compounds were synthesized by solid state reaction route and crystallized in orthorhombic structure with Pnma space group. An average ionic radius 〈rA〉 increased with La-substitution which influenced the physical properties such as the magnetic entropy varying from 4.78 J/kg.K （for x-=0.0） to 3.55 J/kg.K （for x=0.3） and the maximum magnetization at 5 K changing from 3.92 μB （for x=0.0） to 3.59 μB （for x=0.3）. The change in maximum magnetic entropy decreased with increase of A-site average ionic radius. The decrease in magnetic entropy indicated the suppression of lattice disorder that influenced the spin-lattice coupling. The ferromagnetic transition temperature shifted toward room temperature with La substitution. As 〈rA〉 increased, the phase transition changed from first order （for x-=0.0） to second order （for x≥ 0.1） and the refrigeration capacity increased to a significant level. The modest change in magnetic entropy over a wide range of transition temperature might be useful for future active magnetic refrigeration technology.