The surface magneto-optic Kerr effect (SMOKE) was used to investigate the magnetic properties of epitaxial thin films of Co, Ni, and their alloys grown on Cu(100) and Cu(111). The Curie temperature ${\mathit{T}}_{\mathit{C}}$ is higher for the same films of a given thickness on Cu(111) than on Cu(100). All the films show a change in the power-law exponent β of the magnetization density M∼(1-T/${\mathit{T}}_{\mathit{C}}$ ${)}^{\mathrm{\beta }}$ with reducing film thickness. Ni films on Cu(100) undergo a particularly abrupt crossover at ∼7 monolayers (ML) from three-dimensional Heisenberg (β=0.37) to finite-size two-dimensional XY (β=0.23) behavior as the film thickness is reduced. The characteristic power-law exponent β=0.23 of these films appears to be an experimental realization of Kosterlitz-Thouless behavior over a restricted temperature range. A similar, but more gradual crossover occurs for the Ni films on Cu(111) at 8 to 12 ML. The finite-size scaling behavior in the few-monolayers-thickness range is compared with that reported for Ising thin-film behavior. In all instances ${\mathit{T}}_{\mathit{C}}$ extrapolates with decreasing thickness to zero at one monolayer. The dimensionality crossover and finite-size scaling behavior is discussed in the light of our current understanding of spin-wave quantization, anisotropy, and film microstructure.

Using inverse photoemission and photoemission we find that the bulk bands become discretized in highly perfect layer structures, such as Cu on fcc Co(100), Cu on fcc Fe(100), Ag on bcc Fe(100), Au on bcc Fe (100), fcc Co on Cu(100), and bcc Fe on Au(100). The electronic structure is analyzed in the framework of quantum-well states consisting of bulk Bloch functions modulated by an envelope function. The wavelength of the envelope function is determined from the λ/2 interferometer fringes produced by the periodic appearance of quantum-well states with increasing film thickness. Using k conservation, one obtains an absolute measurement of the band dispersion for the s,p bands of Fe, Cu, Ag, and Au. Quantum-well states at the Fermi level are found to be closely connected with oscillatory magnetic coupling in superlattices. They are spin polarized, even in noble metals, due to the spin-dependent band structure of the confining ferromagnet. The oscillation period is half the wavelength of the envelope function. The corresponding wave vector is given by the Fermi wave vector and by the wave vector of the nearest s,p band edge via 2(${\mathit{k}}_{\mathrm{edge}}$-${\mathit{k}}_{\mathit{F}}$). This turns out to be equivalent to Ruderman-Kittel-Kasuya-Yosida theory.

Angle-resolved photoemission is used to determine the energy bands of permalloy (Ni0.8Fe0.2) and compare them to Ni, Co, and Cu. The energy and momentum resolution (≈0.01 eV and ≈0.01 Å−1) is high enough to resolve the magnetically split bands at the Fermi level that are responsible for spin-dependent conductivity and tunneling. For the Σ1 band we find the magnetic exchange splittings δEex=0.27 eV (0.23 eV for Ni), δkex=0.16±0.02 Å−1 (0.12±0.01 Å−1 for Ni), the Fermi velocity vF↑=(0.22±0.02)106 m/s (0.28×106 m/s for Ni, 0.33×106 m/s for fcc Co), and the widths δk↑⩽0.11 Å−1 and δk↓=0.24 Å−1. Compared to Ni, permalloy features a 27% larger magnetic splitting of the Fermi surface and an extremely short mean free path of 4–8 Å for minority spins.

The magnetization reversal in four arrays of micron-size circular holes (antidots) in a Permalloy film has been studied by means of quantitative magneto-optic Kerr vector magnetometry and magnetic force microscopy. The primitive antidot meshes of the arrays investigated here can be classified as square, rectangular, hexagonal, and oblique. The vector magnetometry data show that the hole arrays induce a magnetic anisotropy completely different from that of the unpatterned film, with new hard axes along the directions connecting nearest neighboring holes. Also the coercive field is strongly affected by the pattern. The results of the vector magnetometry analysis indicate that the reversal process takes place through a collective and periodic domain nucleation and expansion process. The domain structure in the remanent state has been investigated by magnetic force microscopy imaging. The images display well-defined domain structures, which are periodic and commensurate with the holes array.

Chiral nanostructured thin films can be produced through precise control of the angle of incidence of a vapor flux concurrent with substrate rotation. The technique has been employed to create unique porous iron thin film structures on Si(100) with a columnar microstructure. Scanning electron microscopy images illustrate columnar iron films produced with azimuthal rotation during sample growth with the incident flux at an angle of 75° with respect to the surface normal. The columns were found to be well isolated with a narrow distribution of diameters, resulting in aspect ratios of approximately 8 to 1. Hysteresis loops reveal the columnar growth induced a large magnetic shape anisotropy relative to that observed for an iron film grown with normal incidence. The evolution of the columnar microstructure was followed from simple oblique deposition (no substrate rotation), giving a fibrous slanted microstructure, to high-speed rotation where a broad size distribution of highly faceted columnar structures was observed. The measured microstructure is related to the observed magnetic properties.