J Mater Sci Technol ›› 2006, Vol. 22 ›› Issue (03): 397-400.

• Research Articles • Previous Articles     Next Articles

Comparison between Top and Bottom NiO-pinning Spin Valves: Effect of Interfacial Roughness on Specular Reflection

Liang SUN, Jun DU, Xiaoshan WU, Shiming ZHOU, Xixiang ZHANG, An HU   

  1. National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China...
  • Received:2005-04-28 Revised:2005-07-05 Online:2006-05-28 Published:2009-10-10
  • Contact: Jun DU

Abstract: Top and bottom NiO-pinning spin valves of Si/Ta/NiO/Co/Cu/Co/Ta and Si/Ta/Co/Cu/Co/NiO/Ta were prepared by magnetron sputtering, and X-ray diffraction and giant magnetoresistance (GMR) ratio were measured in the temperature range from 5 to 300 K. For the bottom spin valve, the interfacial roughness at NiO/Co is much smaller than that of Co/NiO in the top one. The Co/Cu and Cu/Co interfaces have the same roughness in the bottom and the top spin valves. NiO, Co, and Cu layers have (111) preferred orientations in the top one and random orientations in the bottom one. The GMR ratio of the bottom spin valve is larger than that of the top one at all temperatures and their difference increases with decreasing temperature.

Key words: Spin valve, Specular reflection, Interfacial roughness