Anomalous Concentration Dependence of GMR in Fe/Cu Granular Films Prepared by Cluster Beam Deposition

概要

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Fe cluster dispersed F0,X-CLIIOO A- granttlar films have been produced by a cluster beam (CB)technique. X-ray dif['raction and XAFS meastrrernents indicate that the structure of Fe clustersis b.c.c. for x >60, f.c.c. for x< 20 and b.c.c.-I-f.c,c- for 20< x< 60. lVIagnetoresistance (.NIR)does not sattrrate even at an external field of' 140 kOe, probably becatuse Fe clusters are very smalland naagnetic rnornents of Fe atoms at the cluster sttrface display a spin glass and/or superpara-magnetic character. The IVIR value tnonotonically increases with decreasing Fe concentration,showing no maxirnttm. Based trpon the lVI6ssbauer spectra, spontaneous magnetic rnonaents andstructural studies, sttch a?nomalotns concentration dependence of Ml is attributed to the char-acteristic rtaagnetism of the present F6,X-CLIIOO A- granular filuns: Fe clusters are spin glass inthe dilute Fe-f.c.c., antiferrornagnetic in the Ctz-rich f.c.c. and ferronaagnetic in the Fe-rich b.c.c.region.
社団法人日本物理学会の論文
1997-05-15