Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance

Sung Hoon Kim, Byong Sun Chun, Young Keun Kim, Seong Rae Lee

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We have investigated the temperature dependence of tunneling magnetoresistance (TMR) on plasma oxidation time and annealing temperature. Magnetic tunnel junctions comprising Si/SiO2/Ta/CoFe/IrMn/CoFe5/Al1.6 (oxidized)/CoFe5/Ta (in nm) were sputter-deposited. Thin tunnel barriers were formed by oxidizing Al layers under oxygen plasma for 30-70 sec. When needed, post-deposition annealing was carried out at 450-500 K for 20 min under 500 Oe of external magnetic field. The temperature dependence of such samples was measured between 10 K and 300 K using a cryogenic MR tester. The spin polarization behavior was represented as P(T)=P0(1-αT 1.5), where P0 and α are spin polarization value and spin wave parameter, respectively. It appeared that there was an optimum oxidation condition that resulted in the highest P0 (40.3 %) and the lowest a((10±4.742)×10-6 K-1.5). At this condition, the tunnel barrier is thought to possess the least amount of residual Al or magnetic dead layers at the barrier/ferromagnet interface. The sample that underwent 450 K annealing resulted in a slight enhancement in spin polarization.

Original languageEnglish
Pages (from-to)57-59
Number of pages3
JournalMetals and Materials International
Volume9
Issue number1
DOIs
Publication statusPublished - 2003 Feb

Keywords

  • Magnetic tunnel junction
  • Oxidation and annealing
  • Temperature dependence
  • Tunneling magnetoresistance

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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