Evaluation of AlOx in Co/AlOx/Co spin tunneling junctions by XPS

Yuki Otaka, Hideo Kaiju, Mao Nishiyama, Naoki Sakaguchi, Kazuo Shiiki

Research output: Contribution to journalConference articlepeer-review

3 Citations (Scopus)


Oxidation states of AlOx in Co/AlOx/Co spin tunneling junctions were studied using X-ray photoelectron spectroscopy. Co(10nm)/AlOx/Co(50nm) spin tunneling junctions were fabricated on glass substrates by ion-beam mask sputtering. The Al layers were deposited in various thicknesses and were oxidized in pure O2 gas for 24-48 hours at room temperature. Co/AlOx bilayers simultaneously fabricated were analyzed by XPS. The thicker the Al layer is deposited, the more the unoxidized Al remains. MR ratio of the junctions increased as the unoxidized Al decreased, and this result is qualitatively in agreement with the LMTO calculation result. The O/Al ratio of A1Ox layer is about 1.9-2.0, which means existence of the higher order oxides than Al2O3. XPS depth profiles showed that the unoxidized Al remains not only near the interface with Co but also near the surface when the deposited Al layer thickness is thick.

Original languageEnglish
Pages (from-to)431-436
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Publication statusPublished - 2004 Jan 1
EventIntegration of Advanced Micro- and Nanoelectronic Devices - Critical Issues and Solutions - San Francisco, CA, United States
Duration: 2004 Apr 132004 Apr 16

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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