title: Enhanced Magnetocaloric Effect Driven by Interfacial Magnetic Coupling in Self-Assembled Mn3O4-La(0.7)Sr(0.3)MnO3 Nanocomposites.
abstract: 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-La(0.7)Sr(0.3)MnO3 nanocomposites, with varying doping concentrations of Mn3O4 in the form of nanocrystals embedded in the La(0.7)Sr(0.3)MnO3 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 ∼130%) for the nanocomposites with low doping concentrations of Mn3O4, compared to that of pure La(0.7)Sr(0.3)MnO3 thin films. Relative cooling power remain close to those of La(0.7)Sr(0.3)MnO3. The enhanced magnetic phase-transition temperature and magnetocaloric effect are interpreted and evidenced in the framework of interfacial coupling between Mn3O4 and La(0.7)Sr(0.3)MnO3. This work demonstrates the potentiality of self-assembled nanostructures for magnetic cooling near room temperature under low magnetic fields.
authors.affiliation: Department of Physics, National Cheng Kung University , Tainan 701, Taiwan.|Department of Materials Science and Engineering, National Chiao Tung University , HsinChu 300, Taiwan.
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Vandrangi
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , HsinChu 300, Taiwan.
authors.forename: Jan-Chi
authors.initials: JC
authors.lastname: Yang
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing , Beijing 100083, China.
authors.forename: Yuan-Min
authors.initials: YM
authors.lastname: Zhu
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.
authors.forename: Yi-Ying
authors.initials: YY
authors.lastname: Chin
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.
authors.forename: Hong-Ji
authors.initials: HJ
authors.lastname: Lin
authors.affiliation: National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan.
authors.forename: Chien-Te
authors.initials: CT
authors.lastname: Chen
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing , Beijing 100083, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhan
authors.affiliation: Department of Physics, Durham University , Durham DH1, United Kingdom.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Physics, National Cheng Kung University , Tainan 701, Taiwan.
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University , HsinChu 300, Taiwan.|Institute of Physics, Academia Sinica , Taipei 105, Taiwan.
authors.forename: Ying-Hao
authors.initials: YH
authors.lastname: Chu
keywords: complex oxides; magnetocalorics; manganites; nanocomposites; thin films