[en] magnetocaloric effect ; manganites ; magnetic measurements
[en] The magnetocaloric effect in magnetic materials is of great interest nowadays. In this article we present an investigation about the magnetic properties near the magnetic transition in a polycrystalline sample of a manganite Tb0.9Sn0.1MnO3. Particularly, we are interested in describing the nature of the magnetic interactions and the magnetocaloric effect in this compound. The temperature dependence of the magnetization was measured to determine the characteristics of the magnetic transition and the magnetic entropy change was calculated from magnetization curves at different temperatures. The magnetic solid is paramagnetic at high temperatures. We observe a dominant antiferromagnetic interaction below T-n=38 K for low applied magnetic fields; the presence of Sn doping in this compound decreases the Neel temperature of the pure TbMnO3 system. A drastic increase in the magnetization as a function of temperature near the magnetic transition suggests a strong magnetocaloric effect. We found a large magnetic entropy change Delta S-M(T) of about -4 J/kg K at µ0H=3 T. We believe that the magnetic entropy change is associated with the magnetic transition and we interpret it as due to the coupling between the magnetic field and the spin ordering. This relatively large value and broad temperature interval (about 35 K) of the magnetocaloric effect make the present compound a promising candidate for magnetic refrigerators at low temperatures. (c) 2007 American Institute of Physics.
Services Universitaires Pour la Recherche et les Applications Technologiques de Matériaux Électro-Céramiques, Composites, Supraconducteurs - SUPRATECS
Fonds de la Recherche Fondamentale Collective d’Initiative des Chercheurs - FRFC ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS ; Commissariat Général aux Relations internationales - CGRI ; Ministry of Science and Higher Education of Poland ; Kasa Mianowskiego (Poland)
Copyright (2007) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in J. Appl. Phys. 101, 103904 (2007) and may be found at http://link.aip.org/link/?JAPIAU/101/103904/1.