DSpace
 

DSpace at IIT Bombay >
IITB Publications >
Review >

Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/100/2969

Title: Itinerant electron metamagnetism and magnetocaloric effect in rco2-based laves phase compounds
Authors: SINGH, NK
SURESH, KG
NIGAM, AK
MALIK, SK
COELHO, AA
GAMA, S
Keywords: itinerant electron metamagnetism
magnetocaloric effect
laves phase
magnetovolume effect
spin fluctuations
Issue Date: 2007
Publisher: ELSEVIER SCIENCE BV
Citation: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS,317,68-79
Abstract: By virtue of the itinerant electron metamagnetism (IEM), the RCo2 compounds with R = Er, Ho and Dy are found to show first-order magnetic transition at their ordering temperatures. The inherent instability of Co sublattice magnetism is responsible for the occurrence of IEM, which leads to interesting magnetic and related physical properties. The systematic studies of the variations in the magnetic and magnetocaloric properties of the RCo2-based compounds show that the magnetovolume effect plays a decisive role in determining the nature of magnetic transitions and hence the magnetocaloric effect (MCE) in these compounds. It is found that the spin fluctuations arising from the magnetovolume effect reduce the strength of IEM, which subsequently lead to a reduction in the MCE. Most of the substitutions at the Co site are found to result in a positive magnetovolume effect, leading to an initial increase in the ordering temperature. Application of pressure, on the other hand, causes a reduction in the ordering temperature due to the negative magnetovolume effect. A comparative study of the magnetic and magnetocaloric properties of RCo2 compounds under various substitutions and applied pressure is presented. Analysis of the magnetization data using the Landau theory of magnetic phase transitions has shown that there is a strong correlation between the Landau coefficients and the MCE. The variations seen in the order of magnetic transition and the MCE values seem to support the recent model proposed by Khmelevskyi and Mohn for the occurrence of IEM in RCo2 compounds. Metastable nature of the transition metal sublattice in RCo2-based compounds and its role in determining the magnetic and magnetocaloric properties is explained. (c) 2007 Elsevier B. V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.jmmm.2007.04.009
http://dspace.library.iitb.ac.in/xmlui/handle/10054/13811
http://hdl.handle.net/100/2969
ISSN: 0304-8853
Appears in Collections:Review

Files in This Item:

There are no files associated with this item.

View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback