Effect of bias voltage and interdiffusion in Ir-Mn exchange-biased double tunnel junctions

Yoshiaki Saito, M. Amano, K. Nakajima, S. Takahashi, M. Sagoi, K. Inomata

Research output: Contribution to journalConference articlepeer-review

10 Citations (Scopus)

Abstract

Dual-spin-valve-type double tunnel junctions (DTJs) of sputtered Ir-Mn/Co-Fe/AlOx/Co90Fe10 /AlOx/Co-Fe/Ir-Mn having the R(resistance) × A(area) product; RAP ∼ 3.0 kΩ-μm2 were fabricated and annealed at various temperatures (150-400°C) to introduce interdiffusion. There is a relation between the loss of the magnetoresistance (MR) ratio and that of dc bias voltage value at which the MR ratio decreases in half value (V1/2). After annealing at 300°C, both the MR ratio and V1/2 were increased to 42.4% and 872 mV, respectively, with increasing annealing temperature. Annealing above 300-350°C, both MR ratio and V1/2 decreased rapidly. The loss of the MR ratio and that of V1/2 are well explained by considering interdiffusion of O and Mn at the AlOx/Co-Fe/Ir-Mn interfaces. The mechanism for the loss of MR ratio is not only related to the loss of interface polarization, but is also related to the barrier properties, taking into account the spin-independent two-steps tunneling via defect states in the barrier. These results are consistent with the X-ray photoelectron spectroscopy and cross-sectional transmission electron spectroscopy measurements, which indicate the existence of an Al-Mn-O barrier above 300°C.

Original languageEnglish
Pages (from-to)1979-1982
Number of pages4
JournalIEEE Transactions on Magnetics
Volume37
Issue number4 I
DOIs
Publication statusPublished - 2001 Jul 1
Externally publishedYes
Event8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag) - San Antonio, TX, United States
Duration: 2001 Jan 72001 Jan 11

Keywords

  • AlO/Co-Fe/Ir-Mn interfaces
  • Annealing temperature dependences
  • Bias voltage
  • Double tunnel junction
  • Interdiffusion

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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