Magnetic properties and magneto-caloric effect in pseudo-binary intermetallic (Ce,R)₂Fe₁₇ compounds (R = Y, Pr and Dy)

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• 作者：Pablo Á ; lvarez^a ; Pedro Gorria^a ; ^{pgorria@uniovi.es"" rel=""nofollow} ; José ; L. Sá ; nchez Llamazares^b ; Marí ; a J. Pé ; rez^a ; Victorino Franco^c ; Marian Reiffers^d ; Ivan Č ; urlik^d ; Emil Gaž ; o^d ; Jozef Ková ; č ; ^d ; Jes&#xfa ; s A. Blanco^a
• 关键词：A. Magnetic intermetallics ; A. Rare-earth intermetallics ; B. Magnetic properties ; G. Ambient-temperature uses
• 刊名：Intermetallics
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：19
• 期：7
• 页码：982-987
• 全文大小：1209 K

文摘

We have synthesized three pseudo-binary (Ce,R)₂Fe₁₇ intermetallic alloys, where cerium has been partially substituted by R = Y, Pr and Dy, with the aim of tuning the Curie temperature (between 253 and 273 K) for obtaining the maximum magneto-caloric response of the alloys just below room temperature. The analysis of the x-ray powder diffraction patterns show that the three samples crystallize in the rhombohedral Th₂Zn₁₇-type crystal structure (space group ). We report the temperature dependence of the isothermal magnetic entropy change, ΔS_M(T), the magnetic field dependence of its maximum value, ΔS_M^max(H), and the relative cooling power around the second-order magnetic transition for magnetic field changes μ₀ΔH_max = 5 T. The collapse of the normalized ΔS_M(θ)/ΔS_M^max vs. temperature (where θ is a rescaled temperature) into a single master curve allows the extrapolation of ΔS_M(T) curves for higher magnetic field changes, and/or the estimation of the temperature dependence of the magnetic entropy for other 2:17 pseudo-binary compounds. The lower values of ΔS_M^max compared with those of the R₂Fe₁₇ compounds with R = Pr or Nd are explained in terms of the decrease of the saturation magnetization. The magnetic field dependence of the ΔS_M^max indicates that only Pr_1.5Ce_0.5Fe₁₇ alloy roughly follows a mean-field behaviour.