Enhanced Magnetocaloric Effect Driven by Interfacial Magnetic Coupling in Self-Assembled Mn3O4鈥揕a0.7Sr0.3MnO3 Nanocomposites

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• 作者：Suresh K. Vandrangi ; Jan-Chi Yang ; Yuan-Min Zhu ; Yi-Ying Chin ; Hong-Ji Lin ; Chien-Te Chen ; Qian Zhan ; Qing He ; Yi-Chun Chen ; Ying-Hao Chu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：7
• 期：48
• 页码：26504-26511
• 全文大小：470K
• ISSN：1944-8252

文摘

Magnetic refrigeration, resulting from the magnetocaloric effect of a material around the magnetic phase-transition temperature, is a topic of great interest as it is considered to be an alternate energy solution to conventional vapor-compression refrigeration. The viability of a magnetic refrigeration system for magnetic cooling can be tested by exploiting materials in various forms, from bulk to nanostrucutres. In this study, magnetocaloric properties of self-assembled Mn₃O₄鈥揕a_0.7Sr_0.3MnO₃ nanocomposites, with varying doping concentrations of Mn₃O₄ in the form of nanocrystals embedded in the La_0.7Sr_0.3MnO₃ matrix, are investigated. The temperatures corresponding to the paramagnetic-to-ferromagnetic transitions are higher, and the values of change in magnetic entropy under a magnetic field of 2 T show an enhancement (highest being 鈭?30%) for the nanocomposites with low doping concentrations of Mn₃O₄, compared to that of pure La_0.7Sr_0.3MnO₃ thin films. Relative cooling power remain close to those of La_0.7Sr_0.3MnO₃. The enhanced magnetic phase-transition temperature and magnetocaloric effect are interpreted and evidenced in the framework of interfacial coupling between Mn₃O₄ and La_0.7Sr_0.3MnO₃. This work demonstrates the potentiality of self-assembled nanostructures for magnetic cooling near room temperature under low magnetic fields.