Microstructural stability of NiO-containing spin valves annealed at room temperatur.pdfVIP

CPC(HEPNP)，2009．aa(11)：944—948 Chinese Physics C Vo1 33，No 11，Nov．，2009 M icrostructural stability of NiO-containing spin valves annealed at room temperature木 ZHANG Ai—Mei(张爱梅) ，。 CAI Hong—Ling(蔡宏灵)。 DU Jun(杜军) wu Xiao—Shan(吴小山)。； ’ ZHAI Zhang-Yin(翟章印)。 JIA Quan—Jie(贾全杰)。 1(College of Science，Hohai University,Nanjing 210098，China) 2(Lab of Solid State Microstructures，Department of Physics，Nanjing University,Nanjing 210093，China) 3(BSRF，Institute of High Energy Physics，CAS，Beijing 100049，China) Abstract Microstructure of NiO—containing Co／Cu／Co spin valves(CCC—SV1 annealed at room temperature for nearly four years has been studied by synchrotron radiation X—ray difiraction．W ith the annealing time expanding，the thickness of each sub—layer remains nearly unchanged while the interface roughness varies obvi— OUSly compared with that of samples without annealing．The roughness at the interface of NiO／Co decreases with the annealing time increasing for both of the samples with NiO layer on the top(TSV)and under the bottom jSV1 of CCC—SV．On the other hand，the roughness at Co／Cu interface increases with the annealing time expanding for BSV while it decreases for TSV．These results indicate that the structure of TSV is more stable than that of BSV． K ey words interface roughness，X—ray reflectivity，spin valves PACS 07．85．Qe，61．1O．Kw，61．10．Nz 1 Introduction Magnetic multilayers of magnetoresistance(MR) materials have recently attracted great interest for their important scientific meaning and extensive applicationst 一 ． such as magnetic random access memories(MRAM)，as well as in recording media． However．it is dimcult to accurately control the efect of microstructures on the performance．It is necessary to study in detail the microstructure of magnetic mul tilayer in order to further increase the storage density, speed and stability of the memory．Spin valves using antiferromagnetic layer(AFM)as the pinning layer have become more and more applicable because they exhibit rel