日時：7月6日(木) 17:00-18:00

場所：理 C212 会議室

講演者：Dr. Jesus Chaboy

所属：Instituto de Ciencia de Materiales de Aragon,CSIC-Universidad de Zaragoza, Spain

(JSPS fellow)



講演題目：XMCD in rare-earth transition metal (R-M) intermetallic compounds.

(Tales of a magnetometry-ハo so selective)



アブストラクト：

Intermetallic compounds containing rare earths (R) and iron are of great technological significance owing to their industrial applications as high-performance permanent magnets. The intrinsic magnetic properties of these materials are determined by the exchange interaction between the R-4f and Fe-3d electrons. This interaction takes place through the hybridization of the Fe 3d states with the 5d ones of the rare-earth. Consequently, the study of the R-5d states is of great significance to the search of new advanced magnetic materials within the R-Fe series.

The magnetic characterization of these 5d states is, however, not achieved by using standard magnetic probes. Consequently, the development of the x-ray magnetic circular dichroism (XMCD) technique evoked a far-reaching interest. XMCD gained popularity due to the possibility of obtaining an element-specific quantitative determination of spin and orbital magnetic moments through sum-rule analyses of experimental spectra. In addition, one of the most promising capabilities of XMCD concerning rare earths lies on the possibility of disentangling the magnetic contribution of the 5d and 4f states through an adequate choice of the absorption edge. Unfortunately, the XMCD expectations focused in lanthanides magnetism have not been completely fulfilled,

In this work we review the latest progress into the understanding of the XMCD in R-M intermetallics. It is demonstrated that in order to properly account for the XMCD spectra recorded at the lanthanides L2,3-edges, a non-negligible contribution of the transition metal has to be considered. Similarly, the magnetic state of the rare-earth is influencing the K-edge of the transition metal. Consequently, by correctly accounting these mixed effects it is possible to revealing the transition-metal magnetism by tuning the rare-earth absorption edges and, conversely, the rare-earth magnetism by looking at the transition metal.



担当： 圓山　裕（理学）内線7386





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