Zn0.97Cu0.03O films were prepared by pulsed-laser deposition on c-cut sapphire substrates under various conditions in order to investigate the growth-dependent properties of the films. All the films exhibit room temperature ferromagnetism. Samples deposited at low temperature and low pressure show large saturation magnetization Ms. Moreover, the enhancement of Ms was observed in films annealed both in vacuum and in Zn vapor. However, postannealing in air led to the remarkable reduction of ferromagnetism. The results show that the itinerant electrons introduced by oxygen-deficient or Zn-rich atmospheres may play a significant role in room temperature ferromagnetism observed in this ZnCuO dilute magnetic semiconductor. It is consistent with carrier-induced ferromagnetism. The magnetization strongly depends on the appearance of free carriers and is relatively insensitive to whether they arose from VO or/and Zni.

Room temperature ferromagnetism was observed in n-type Fe-doped In2O3 thin films deposited on c-cut sapphire substrates by pulsed laser deposition. Structure, magnetism, composition, and transport studies indicated that Fe occupied the In sites of the In2O3 lattice rather than formed any metallic Fe or other magnetic impurity phases. Magnetic moments of films were proved to be intrinsic and showed to have a strong dependence on the carrier densities, which depended on the Fe concentration and its valence state as well as oxygen pressure.

Soft/hard bilayers consisting of a FeAu layer with different thicknesses and a 20nm L10-FePt layer have been fabricated by magnetron sputtering and postannealing. FeAu soft layer not only can promote the ordering degree of FePt layer because of the small lattice mismatch between them and the diffusion of Au atoms into FePt boundaries, but also can reduce the coercivity due to the soft/hard exchange coupling. The results of x-ray photoelectron spectroscopy indicate that a graded interface is formed in the FeAu/FePt bilayer after annealing, which is beneficial to reduce the pinning field. The magnetization reversal in the FeAu/FePt exchange-spring media occurs by the nucleation and propagation of a domain wall from soft layer into hard layer.

Films of ZnO doped with magnetic ions Mn and Co and, in some cases, with Al have been fabricated with a very wide range of carrier densities. Ferromagnetic behavior is observed in both insulating and metallic films, but not when the carrier density is intermediate. Insulating films exhibit variable range hopping at low temperatures and are ferromagnetic at room temperature due to the interaction of the localized spins with static localized states. The magnetism is quenched when carriers in the localized states become mobile. In the metallic (degenerate semiconductor) range, robust ferromagnetism reappears together with very strong magneto-optic signals and room temperature anomalous Hall data. This demonstrates the polarization of the conduction bands and indicates that, when ZnO is doped into the metallic regime, it behaves as a genuine magnetic semiconductor.

Pulsed laser deposition is a very promising experimental technique for growing layers of nanoscale thickness. In this paper, the growth of a perovskite structured film grown on a perovskite substrate is simulated using the Monte Carlo procedure and LaMnO3 is taken as an example. In the model, we consider the motion of the La and Mn atoms, and assume the oxygen atoms follow the metal atoms. The quality of the film is controlled by three parameters: namely, the temperature of the substrate, the kinetic energy of the atoms, and the average coverage of each pulse. The simulated results show that the quality of the films is strongly dependent on the three parameters. We analyzed the composition of the films layer by layer and find an interesting phenomenon: if the deposition conditions are not optimal, the fraction of wrong atoms fractional mismatch presents odd-even staggering as the number of deposited atom layers increases.

A series of Zn1-xCoxO thin films with the atomic fraction, x, in the range of 0.03-0.10 were deposited on glass substrates at room temperature by magnetron co-sputtering technique and subsequently coupled with the post-annealing treatment for half hour at different temperatures (350℃and 500℃) under vacuum. A systematic study was done on the structural, optical and magnetic properties of Zn1-xCoxO thin films as a function of Co concentration and annealing temperature. X-ray diffraction and UV-vis spectroscopy results indicated that there are not any secondary phases and Co2+ substituted for Zn2+ of ZnO host. Magnetic hysteresis loops were observed at room temperature, indicating that both the as-deposited samples and the annealed ones exhibit the room temperature ferromagnetism. It was also found that the magnetic saturation moment per Co atom decreases with increasing Co concentration, while the post-annealing treatment can enhance the magnetic moment of the films effectively.

[Co(0.6 nm)/ZnO(x nm)]60 (x=0.3-3) films were deposited on glass substrates by magnetron sputtering, and then annealed in vacuum. The large negative magnetoresistance of-10.4% is observed in the as-deposited [Co(0.6nm)/ZnO(0.4nm)]60 film. When ZnO layer thickness is increased from 0.3 to 3nm, MR ratios of the as-deposited Co/ZnO films are gradually decreased and MR ratios of the annealed films are increased, which might be attributed to the transformation of the structures from the multilayers to granular films during annealing. And the postannealing process makes the magnetism of the films transform from superparamagnetism to ferromagnetism due to Co precipitation in granular films after annealing.

The L10 CoPt films with (001) preferred orientation are achieved by fabricating on the glass substrates and post annealing at 600℃ for 30min. The preferred orientation of [ZrO2/CoPt]n/Ag films dependence of the Ag underlayer thickness, ZrO2 and CoPt interlayer thickness is investigated. A large perpendicular magnetic anisotropy and a nearly perfect L10 CoPt (001) texture are obtained in the [ZrO2 (3nm)/CoPt (5nm)]3/Ag (10nm) film. The existence of ZrO2 plays an important role in reducing the intergranular interactions and in determining the size of CoPt grains. Magnetic reversal in textured CoPt films are close to a Stoner-Wolfarth rotation.

(In1-xFex)2O3 (x=0.02,0.05,0.2) powders were prepared by a solid state reaction method and a vacuum annealing process. A systematic study was done on the structural and magnetic properties of (In1-xFex)2O3 powders as a function of Fe concentration and annealing temperature. The X-ray diffraction and high-resolution transmission electron microscopy results confirmed that there were not any Fe or Fe oxide secondary phases in vacuum-annealed (In1-xFex)2O3 samples and the Fe element was incorporated into the indium oxide lattice by substituting the position of indium atoms. The X-ray photoelectron spectroscopy revealed that both Fe2+ and Fe3+ ions existed in the samples. Magnetic measurements indicated that all samples were ferromagnetic with the magnetic moment of 0.49-1.73 mB/Fe and the Curie temperature around 783 K. The appearance of ferromagnetism was attributed to the ferromagnetic coupling of Fe2+ and Fe3+ ions via an electron trapped in a bridging oxygen vacancy.

FePt (50nm) and [FePt(a nm)/MgO(b nm)]5/glass (a=1,2,3; b=l,2,3) films were prepared by radio frequency (RF) magnetron sputtering technique, and then were annealed at 600℃ for 30min. The effect of MgO layer thickness on the structures and magnetic properties of the FeWMgO multilayers was investigated. The coercivities and inter-grain interactions of the FeWMgO films were decreased, yet the degree of (001) texturing drastically increased with the increase in MgO layer thickness when the FePt layer thickness was fixed. Thus, the FeWMgO films with appropriate coercivities, high perpendicular anisotropy, and weak intergrain interactions were obtained by controlling the MgO layer thickness. Overall, these results indicate that the FeWMgO nanostructured films are promising candidates for future high-density perpendicular recording media.