Nanoscale structural evolution and associated changes in magnetoresistance in the granular FexAg100minus;xthin films

摘要

The microstructure of sputterhyphen;deposited granular FexAg100minus;xthin films (0x60) has been investigated by using a high resolution transmission electron microscope. Forxle;14 at.thinsp;percnt; Fe, two kinds of morphological regions exist, i.e., the crystallized and the highly disordered. As thexchanges within 20ndash;36 at.thinsp;percnt; Fe, small clusters with sizes around 1 nm are formed in the films. Further increase ofxleads to the crystal grain fining and crystal frustration. The observed microstructural evolution in the films with the increase of Fe content can be correlated with the evolution of giant magnetoresistance at 4.2 K in the Fehyphen;Ag films: a linear relationship of the magnetoresistance ratio, Dgr;rgr;/rgr;, withHforxle;20 at.thinsp;percnt;, the saturation trend and the decrease of Dgr;rgr;/rgr; forxge;36 at.thinsp;percnt; Fe.