Acta Metallurgica Sinica (English Letters) ›› 2009, Vol. 22 ›› Issue (2): 153-160.DOI: 10.1016/S1006-7191(08)60083-6

• Research paper • Previous Articles    

Current spin polarization and spin injection efficiency in ZnO-based ferromagnetic semiconductor junctions

Gang JI1,2,3, Ze ZHANG1, Yanxue CHEN3, Shishen YAN3, Yihua LIU3,Liangmo MEI3   

  1. 1) Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology,Beijing 100124, China\par\noindent
    2) Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
    3) School of Physics and National Key Laboratory of Crystal Materials, Shandong University,Jinan 250100, China
  • Received:2008-03-04 Revised:2008-06-12 Online:2009-04-25 Published:2009-10-10
  • Contact: Gang JI

Abstract:

[FeNi(3~nm)/Zn1- xCoxO(3~nm)]2/ZnO(d nm)/[Zn1-xCoxO(3 nm)/Co(3 nm)]2 (d=3 and 10) semiconductor junctions were prepared by magnetron sputtering system and photolithography. The spin valve effect was observed in these junctions because the utility of the ferromagnetic composite layers acted as soft and hard magnetic layers. The electrical detection was performed by measuring the magnetoresistance of these junctions to investigate the current spin polarization αsc in the ZnO layer and the spin injection efficiency η of spin-polarized electrons. αsc was reduced from 11.7% (and 10.5%) at 90 K to 7.31 % (and 5.93 %) at room temperature for d=3 (and d=10). And η was reduced from 39.5 % (and 35.5 %) at 90 K to 24.7 % (and
20.0 %) at room temperature for d=3 (and d=10).

Key words: Spin injection, Electrical detection, Magnetoresistance, Room temperature ferromagnetic semiconductor, Ferromagnetic composite layers