Scanning tunneling spectroscopy of Ni/W(110): bcc and fcc properties in the second atomic layer

Abstract

Nickel islands are grown on W(110) at elevated temperatures. Islands with a thickness of two layers are investigated with scanning tunneling microscopy. Spectroscopic measurements reveal that nanometer sized areas of the islands exhibit distinctly different apparent heights and dI/dV spectra. Spin polarized and paramagnetic band structure calculations indicate that the spectral features are due to fcc(111) and bcc(110) orientations of the Ni film, respectively.

Predicting epitaxial orientations and lattice structure in ultrathin magnetic thin films

“…[11][12][13] However, massive studies of the epitaxial Fe, Co, and Ni ultrathin films suggest that the differences in crystal structures between film and substrate can lead to unpredictable fundamental magnetic properties. For instance, it has been proved experimentally that metastable bcc structure of Co [14][15][16] or Ni 17,18 and the hcp structure of Fe 19,20 or Ni [21][22][23] can be stabilized in ultrathin films, which are, however, difficult to achieve in bulk materials. The unstable crystal structures provide an extra degree of freedom to tailor film morphology and thus to improve the physical property.…”