Magnetic and magnetocaloric properties of Gd_{3鈭?span style='font-style: italic'>x}Tb_xGa₅O₁₂ (x=0, 1, 2, 3) garnets

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• 作者：C.P. Reshmi^a ; S. Savitha Pillai^a ; K.G. Suresh^b ; Manoj Raama Varma^a ; ^{manojraamavarma@yahoo.co.uk}
• 关键词：Rare earth garnet ; Effective magnetic moment ; Arrott plot ; Magnetocaloric effect
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2012
• 期刊代码：31_03048853
• 类别：ph
• 出版时间：June, 2012
• 卷：324
• 期：12
• 页码：1962-1966
• 文件大小：852 K

摘要

The structure and magnetocaloric properties of Tb substituted Gd₃Ga₅O₁₂ garnets have been investigated. The structural refinement of X-ray diffraction patterns show that Gd_3鈭?em>xTb_xGa₅O₁₂ (x=0, 1, 2, 3) are isostructural, with the symmetry of a cubic space group . The temperature dependence of magnetization studies indicate that all the samples follow Curie-Weiss paramagnetic behavior above 25 K and the effective magnetic moment increases with Tb concentration. The low temperature magnetization studies suggest that there exists a field dependent antiferromagnetic ordering of rare earth ions in Tb substituted Gd₃Ga₅O₁₂, which in turn leads to a lower magnetic moment in Gd_3鈭?em>xTb_xGa₅O₁₂ (x=1, 2, 3), compared to that of Gd₃Ga₅O₁₂. Magnitude of field corresponding to the antiferromagnetic ordering is found to be dependent on temperature as well as on Tb concentration. Magnetocaloric effect analysis confirms that Tb substitution enhances the magnetic entropy change at higher temperatures and Gd_3鈭?em>xTb_xGa₅O₁₂ (x=1, 2, 3) are better candidates than Gd₃Ga₅O₁₂ for low fields and low temperature magnetic refrigeration applications.