TITLE:
The Magnetoresistance of Nanostructured Co-ZnO Films with ZnO Buffer-Layers
AUTHORS:
Xiaoli Li, Long Cheng, Long Cheng, Yalei Wang, Yan Gao, Zhiyong Quan, Xiufang Qin, Harry J. Blythe, Gillian A. Gehring, Xiaohong Xu
KEYWORDS:
Magnetron Sputtering, Magnetoresistance, ZnO Buffer-Layer
JOURNAL NAME:
Materials Sciences and Applications,
Vol.5 No.14,
December
3,
2014
ABSTRACT: Co-ZnO films were prepared on oxidised silicon by magnetron sputtering at room temperature both with and without a ZnO buffer-layer. The Co-ZnO films consisted of Co particles dispersed in a semiconductor matrix. The combination of a Co-ZnO layer and a ZnO buffer-layer has a higher magnetoresistance than the Co-ZnO layer alone on an insulating Si substrate. The causes of this effect were investigated using X-ray photoelectron spectroscopy, depth profiling using Auger electron spectroscopy and electrical resistance as well as measurements of the change in the saturation magnetisation, the field cooled- and zero field cooled-magnetisation. This work has shown clearly what criteria are needed to optimise the magnetoresistance and how these conditions may be met by adding a buffer-layer thus making granular films based on ZnO more suitable for applications as field sensors.