Title :
High-frequency study of magnetic and magnetoimpedance features of granular nanostructures
Author :
S. Tarapov;T. Bagmut;A. Granovsky;V. Derkach;Yu. Kalinin;S. Nedukh;F. Yildiz;B. Aktas;L. Tagirov
Author_Institution :
Inst. of Radiophys. & Electron., NAS of Ukraine, Kharkov, Ukraine
fDate :
6/26/1905 12:00:00 AM
Abstract :
For granular nanostructured system (Co/sub 40/Fe/sub 40/B/sub 20/)/sub x/(SiO/sub 2/)/sub 1-x,/ the FMR absorption and derivative lines were detected for metal phase concentrations X=37-53% in the frequency band 10-50 GHz. As well GMR was measured for these specimens. The analysis of the FMR lineshape demonstrates a presence of the non-collinear magnetic phase such as the asperomagnetic or superparamagnetic ones for insulating compositions below the percolation threshold (X<47%). The GMI was observed for compositions close to the percolation concentration. The GMI was observed only for samples with noticeable tunnel-type magnetoresistance. It means that the origin of GMI in the samples is connected with high frequency spin-dependent tunneling. Since the GMI amplitude at 30-50 GHz (/spl delta/T/T=0.46%) is approximately the same as that for MRE in transmission mode at infrared frequencies, it confirms that spin-dependent tunneling does not depend on frequency in a wide frequency range.
Keywords :
"Nanostructures","Magnetic resonance","Giant magnetoresistance","Magnetic tunneling","Iron","Absorption","Gas detectors","Phase detection","Phase frequency detector","Magnetic analysis"
Conference_Titel :
Physics and Engineering of Microwaves, Millimeter, and Submillimeter Waves, 2004. MSMW 04. The Fifth International Kharkov Symposium on
Print_ISBN :
0-7803-8411-3
DOI :
10.1109/MSMW.2004.1346131