Effect of Columnar Structures on Exchange Anisotropy Field in Magnetoresistive NiO/NiFe Bilayers

  • Jai-Young Kim (Electro-Mechanics Lab., System & Control Sector, Samsung Advanced Institute of Technology, Suwon, Korea) ;
  • Gyeong-Su Park (AE Lab. TCS Center, Samsung Advanced Institute of Technology, Suwon Korea) ;
  • Jae-Chul Ro (Department of Metallurgical Engineering, Sung-Kyun-Kwan University, Suwon. Korea) ;
  • Su-Jeong Suh (Department of Metallurgical Engineering, Sung-Kyun-Kwan University, Suwon. Korea)
  • Published : 1999.09.01

Abstract

A series of NiO/NiFe bilayer films are deposited with the variation of Ar sputtering pressure for the NiO layers only. As the pressure for the NiO layers increases, the exchange anisotropy field (HEX) decreases gradually and becomes extinct at 2.5 mTorr, at which the maximum coercive force (HC) in the NiO/NiFe films is obtained. Randomly oriented columnar structures with HEX a few tens of Oe and oriented columnar structures with zero HEX are observed in the NiP layers by highvoltage hihg-resolution transmission electron microscopy. The vanishing of the HEX in the oriented structures is attributed to the lack of exchange anisotropy energy (EEX) between NiO and NiFe layers, which results in little contribution of interfacial unidirectional pinning anisotropy to the interface of NiO/NiFe bilayer.

Keywords

References

  1. Phys. Rev. v.B43 B. Dieny;V. S. Speriosu;S. S. Parkin;B. A. Gurney;D. R. Wilhoit;D. Mauri
  2. IEEE Trans. Magn. v.30 C. Tsang;R. E. Fontana;T. Lin;D. E. Heim;V. S. Speriosu;B. A. Gurney;M. L. Williams
  3. J. Appl. Phys. v.52 C. Tsang;S. K. Decker
  4. IEEE Trans. Magn. v.31 T. Lin;C. Tsang;R. E. Fontana;J. K. Howard
  5. Appl. Phys. Lett. v.60 M. J. Carey;A. E. Berknowitz
  6. Appl. Phys. Lett. v.65 T. Lin;D. Mauri;N. Staud;C. Hwang;J. K. Howard
  7. IEEE Trans. Magn. v.32 Chih-Huang Lai;Thomas C. Anthony;Eiji Iwamura;Robert L. White
  8. Appl. Phys. Lett. v.72 D. G. Hwang;S. S. Lee;C. M. Park
  9. J. Appl. Phys. v.81 De-Hua Han;Jian-Gang Zhu;Jack H. Judy
  10. Phys. Rev. v.B35 A. P. Malozemoff
  11. Phys. States Solidi v.28 C. Schlenker
  12. IEEE Trans. Magn. v.32 J. Zhang;R. M. White
  13. J. Appl. Physics. v.63 A. P. Malozemoff