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The electronic and magnetic structures of both face-centered-cubic (FCC) and body-centered-cubic (BCC) FM 1− x Pd x (FM representing Co, Ni) ordered alloys at x=0.25, 0.5, 0.75 have been calculated using the first principles linearized augmented plane-wave method with the local spin density approximation. The results show that FCC-Co 1− x Pd x , BCC-Co 1− x Pd x and FCC-Ni 1− x Pd x are ferromagnetic at all the compositions considered, but BCC-Ni 1− x Pd x is ferromagnetic only at x =0.25 and 0.5 and is paramagnetic at x =0.75. The calculation also indicates that, except BCC-Ni 1− x Pd x at x =0.75, the Pd atoms are strongly spin polarized while the magnetic moments of Ni and Co atoms are significantly enhanced in the Ni 1− x Pd x and Co 1− x Pd x alloys compared to their pure metal phases.

Epitaxial growth of Ni thin films on GaAs(0 0 1) and their magnetic property have been investigated using reflection high energy electron diffraction and magneto-optical Kerr effect. The result shows that a body-centered-cubic (BCC) phase of Ni which does not exist in nature can grow epitaxially up to 2.5 nm on the GaAs(0 0 1) substrate, and it is determined to be ferromagnetic showing a four-fold in-plane magnetic anisotropy with the easy axes along the 〈1 0 0〉 directions.

To study the optical properties of the metal–insulator granular films, a series of Ni x SiO 2(1 −x ) and Au x SiO 2(1 −x ) granular films was made with variation of x and the annealing process. The complex dielectric function was measured in the 1.5–4.8 eV photon energy range. New spectral features were found in the dielectric functions. For AuSiO 2 samples, the new peak in e 2 spectra is seen around 2 eV, especially for x =0.67. The e 1 spectra change continuously from positive to negative at the low–photon energy range, resulting in a true e 1 associated with the plasmon occurred at 2.0–2.5 eV and at about 3.6 eV for the Au- and Ni-based films, respectively. Comparing to previous data, the experimental results obtained in this work provide richer information to understand better the optical properties of the metal-granular films that are not well predicated by the theoretical model. The effect will be useful in the metallic multilayer structure design applications.

A series of CoxAg100−x granular films was annealed at 100, 250, 400, and 500 °C, respectively. Both the dielectric function and polar Kerr effect were measured using a spectroscopic ellipsometer and a magneto-optical Kerr spectrometer in the 1.5–4.5 eV photon energy range. It was found that the Kerr effect was greatly enhanced with increasing annealing temperature, especially for those samples having low Co compositions. After annealing, the strong resonance peaks appear in the 3.7–4.1 eV range. For the typical sample with x=6, the maximum Kerr rotation angle is about 0.26° near 4.0 eV after annealing at 500 °C. Through data analysis, the large negative peak at about 3.85 eV is attributed to the plasma edge of Ag, and the positive peak near 4.0 eV is attributed to the new magneto-optical structure and the properties of the granular film. The larger short-wavelength Kerr effect will be useful for increasing magneto-optical data-storage density.

A series of NixSiO2(1−x) granular films was prepared by ion sputtering, and some of them were annealed. Both the complex dielectric function and magneto-optical polar Kerr spectra of the samples were measured in the 1.5–4.5 eV photon energy range at room temperature. There are broad peaks in the 2.5–3.5 and 3.2–4.5 eV range in the Kerr rotation and ellipticity spectra, respectively. The Kerr intensities increase with increasing Ni composition. For sample x=0.65, the Kerr peaks are redshifted, with reduced intensities after annealing. Both the off-diagonal terms of the dielectric tensor and the optical constants are attributed to enhancement of the Kerr effect in a particular spectral range for the metal–insulator granular films.

For the granular type of Co-Ag (1.8 nm)/Ag multilayers with the Co contents of 22, 45, and 65 at%, the magneto-resistance ratio ((Delta) R/R) has a maximum found with respect to the AG spacer layer thickness. It is found that with increasing Co content the (Delta) R/R peak shifts towards thicker AG layers. For the Co-Ag/Ag multilayers with low Co contents, (Delta) R/R increases monotonically with increasing magnetic layer thickness, but has a maximum near the magnetic layer thickness of 2.2 nm for the sample having a higher Co content. The peak is thought as a result of the antiferromagnetic (AFM) coupling between the nearest Co clusters in neighboring magnetic layers. In the high field region, the magnetization and the square root of (Delta) R/R vary as a linear function of the reciprocal applied field for all multilayers. In the low field range, they are proportional to the applied field for samples with thin magnetic layers.

The electronic and magnetic structures of both face-centered-cubic (FCC) and body-centered-cubic (BCC) Co 1− x Pd x ordered alloys at x =0.25, 0.50, 0.75 have been calculated using the first principles linearized augmented plane-wave (LAPW) method with the local spin density approximation (LSDA). It is found that both FCC-Co 1− x Pd x and BCC-Co 1− x Pd x are ferromagnetic at all the compositions considered above. It is also noticed that the Pd atoms in these situations are strongly spin-polarized, meanwhile magnetic moments of Co are significantly enhanced.