Photothermally modulated magnetic resonance applied to the study of the magnetic phase transition in gadolinium thin films

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• 作者：M.E. Soffner^a ; J.C.G. Tedesco^a ; F. Pedrochi^b ; G.Z. Gadioli^a ; M.A.B. de Moraes^a ; A.O. Guimarã ; es^c ; E.C. da Silva^c ; A.M. Mansanares^a ; ^{manoel@ifi.unicamp.br}
• 关键词：Magnetic resonance ; Photothermics ; Thin films ; Gadolinium ; Phase transition
• 刊名：Thin Solid Films
• 出版年：2012
• 出版时间：29 February 2012
• 年：2012
• 卷：520
• 期：9
• 页码：3634-3640
• 全文大小：613 K

文摘

We explore the photothermally modulated magnetic resonance technique to investigate gadolinium thin films deposited on fused quartz substrate, as a function of thickness and thermal treatment, around the magnetic phase transition temperature. It has been observed that the maximum amplitude of the photothermally modulated magnetic resonance (PM-MR) signal takes place near the phase transition temperature, similarly to the magnetocaloric effect, for which Gd has been the prototype material. The reason is that both depend on the temperature derivative of the magnetization, which maximizes at the phase transition. Besides, there is a narrowing of transition with thermal treatment, confirming that thermal treatment stabilizes the film structure. For frequency scan measurements, the heat diffusion in a two-layer system was considered, and a depth profile study was carried out in order to investigate heterogeneities along the film thickness. From the PM-MR response as a function of the modulation frequency it was possible to estimate the thermal properties of the Gd film. Magnetization, X-ray and electron spin resonance measurements were used to complement the analysis and support the conclusions.