Magnetic phases of Co/Ge(1 1 1) studied using surface magneto-optic Kerr effect

J. S. Tsay, H. Y. Nieh, Y. D. Yao, Y. T. Chen, W. C. Cheng

Research output: Contribution to journalConference article

13 Citations (Scopus)

Abstract

Co/Ge(111) films are nonferromagnetic up to 9.5 monolayers as deposited at 300 K. Upon cryogenic treatments, magnetic phases are experimentally resolved for Co/Ge(111) films thinner than 12 monolayers using the surface magneto-optic Kerr effect technique. Systematic investigations of the magnetic properties for Co/Ge(111) films revealed a transition of nonferromagnetism to ferromagnetism at low temperatures. The transition temperature increases from below 125 K to above 300 K as the cobalt coverage increases from 6.3 to 12 monolayers. The critical exponent β in the power law relationship of magnetization is about 0.23 that is close to the value expected by a two-dimensional XY model. Auger electron spectroscopy measurements suggest the co-existence of a pure cobalt and a Co-Ge compound layers in the nonferromagnetic Co/Ge(111) films.

Original languageEnglish
Pages (from-to)226-230
Number of pages5
JournalSurface Science
Volume566-568
Issue number1-3 PART 1
DOIs
Publication statusPublished - 2004 Sep 20
EventProceedings of the 22nd European Conference on Surface Science - Prague, Czech Republic
Duration: 2003 Sep 72003 Sep 12

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Keywords

  • Auger electron spectroscopy
  • Cobalt
  • Germanium
  • Magnetic films
  • Magnetic measurements
  • Magnetic phenomena (cyclotron resonance, phase transitions, etc.)
  • Metal-semiconductor magnetic thin film structure

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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