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Title: Electronic properties of pseudomorphic metallic films: Photoemission and inverse photoemission measurements

Miscellaneous ·
OSTI ID:7167130

The methods used to grow pseudomorphic fcc films of Ni, Co, and Fe on Cu(001) are described. High-quality epitaxial films are produced by vapor deposition in an ultra-high vacuum environment on suitably prepared substrates. The morphology of these films is characterized using a variety of experimental techniques: Auger electron spectroscopy, low-energy electron diffraction, reflection high-energy electron diffraction, and thermal desorption spectroscopy of adsorbed hydrogen. The magnetic properties of the films are measured with a surface magneto-optic Kerr effect magnetometer. The occupied and unoccupied electronic band dispersions and critical point energies are determined with photoemission and inverse photoemission measurements. These measurements are used as eigenvalues for an empirical combined interpolation scheme bandstructure calculation of the energy bands along the fcc(001) surface normal. Results are presented for Cu(001), Ni(001), Co(001), and paramagnetic Fe(001). Changes in the unoccupied electronic states in the ultrathin film limit are determined for Co and Fe films on Cu(111). The Co films exhibit a bulk-like electronic structure similar to hcp Co(0001) down to films one atomic layer thick. The low-spin ferromagnetic phase of fcc Fe is produced on Cu(111) for films below 5 atomic layers thick. Above this thickness, the Fe films revert to a bulk-like bcc(110) phase. The development of the electronic structure is measured for ultrathin Cu films grown on a fcc Co(001) substrate. The Cu 3d band is significantly narrowed for films 1 atomic layer thick and bulk-like for films 3 atomic layers thick (one fcc unit cell). The s, p band exhibits quantum-well states due to the discretization of reciprocal space in the direction perpendicular to the film surface. These quantum-well states are related to oscillatory magnetic exchange coupling in ferromagnetic nonmagnetic superlattices.

Research Organization:
Pennsylvania State Univ., University Park, PA (United States)
OSTI ID:
7167130
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English