Pulsed laser deposition was used to deposit thin films of calcium hydroxylapatite (Calo(P04)6(OH)z), or HA, on polished substrates of Ti-6A1-4V. Thin films of pure, crystalline HA, uncontaminated by other calcium phosphate phases, were deposited over a range of temperatures between 400 and 800 "C. The HA films were polycrystalline with a preferred (001) crystallographic orientation, as determined by transmission electron microscopy and x-ray diffraction. Adhesion of the HA films to the Ti-6A1-4V substrates was excellent when films were deposited at temperatures 5 600 "C; in a scratch test, mean pressures of ca. 10'' Nm-' produced conformational cracking in a film deposited at 600 "C, but no decohesion from the substrates.

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The magnetic and structural properties of pulsed laser deposited MnZn–ferrite films have been examined. The results show that the uniaxial anisotropy, ferromagnetic resonance linewidth and coercive force are strongly influenced by the microstructure of the films, and the saturation magnetization and first-order magnetocrystalline anisotropy constant depend on intrinsic properties such as composition and cation site occupation. A comparison of bulk and film magnetic properties shows that the magnetic properties of the films are comparable to the bulk, which makes pulsed laser deposition ferrite films a prime candidate for thin film high-frequency microwave device applications.

One of the apparent effects of Y on the growth of Cr20~ scales, based on inert marker studies, is a change in growth mechanism from predominant cation diffusion to predominant anion diffusion [I-3]. The interpretation of inert marker studies has always been open to question, and a recent study of the mechanisms of growth of a-Al203 scales using ~60 tracer techniques [4] has demonstrated that the results of inert marker studies can, indeed, be misleading. Results of ~80 tracer oxidation experiments conducted with Y-implanted and Y-free cr are reported in this paper, which demonstrate that Y implantation aoes change the mechanism of oxide growth.EXPERIMENTAL PROCEDURE: Very high purity specimens of chromium [5], polished to a 0.3 um alumina finish, were implanted on either one or both sides with 2 x I0 .6 Y atoms/cma at 70 keV. According to RBS analysis [6], the maximum concentration of Y, which was located 17 nm below the surface of the specimen, was 7.2at%. The distribution of Y was essentially Gaussian, and, according to SIMS analysis, the impurity levels were not significantly higher than those for unimplanted Cr.Details of the apparatus for conducting tracer oxidation experiments are described elsewhere [7]. Specimens were placed in the apparatus which was evacuated overnight, after which 160 z was introduced at 5 x lO -3 torr pressure, and the specimen was heated to 900~ Oxidation was carried out in 1602 for 1Oh at 9DO~ at which time the system was evacuated, and the specimen was cooled to room temperature. The next day the specimen was reheated and oxidized for an additional 5h at 90O~ in 1602 . The gas was then changed from 160~ to 180~ while the specimen was maintained at 900~ ~ Oxidation was continued for an additional 5h in 18Q2, after which the specimen was cooled in 1802 to room temperature. RESULTSAND DISCUSSION: The oxide scale on Y-impl'anted Cr was about O.3~m thick and comprised three layers. The oxide adjacent to the metal/scale interface was polycrystalline *Electrochemical Society Student Member. **Electrochemical Society Active Member Cr203 (0.1-0.2 um grain size) with Y segregated to the grain boundaries [8]. Nearer the scale/gas interface the scale comprised a mixture of Y-rich oxide particles (probably YCr03 [9]), and Cr203 grains that were about 25 nm in diameter. Immediately adjacent to the scale/gas interface the scale was Cr203 with a grain size of about 50 nm. These microstructural features are shown in Fig. l, which is a STEM bright field image of a cross section of the scale in the vicinity of the scale/gas interface. SIMS analyses were performed with a PhysicalElectronics SIMS-II system used in conjunction with a differential ion gun operated with a 4 keV xenon beam (0.5 mm diameter) at 33 ~ off the specimen normal. The beam was rastered over an area of 2.5 x 3 mm, and was electronically gated to analyze the central 10% of the sputter crater. Figure 2 is a SIMS sputter-depth profile of 8.5um-thick C~03 on unimplanted Cr. This is 25X thicker than obtained on Y-implanted Cr. The Cr mO...

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The successful use of pulsed laser deposition (PLD) to fabricate thin film superconductors has generated interest in using the technique to deposit thin films of other materials. The compositional fidelity between laser target and deposited film and the ability to deposit films in reactive gas environments make the PLD process particularly well suited to the deposition of complex multicomponent materials. Cheung and Sankur recently provided an excellent review of the PLD field, including a table of over 100 elements, inorganic and organic compounds, andsuperlattices that have been laser evaporated. Over 75 of these materials were deposited as thin films.The goal of this article is to provide an introduction to some of the newer applications of PLD for thin film fabrication. Four classes of materials are highlighted: ferroelectrics, bioceramics, ferrites, and tribological materials. Ferroelectric materials are structurally related to the high-temperature superconducting oxides and therefore are a direct extension of the recent superconducting oxide work. Bioceramics are dissimilar in structure and application to both ferroelectrics and superconducting oxides, but they are complex multicomponent oxides and, therefore, benefit from the use of PLD. Ferrites, also complex, multicomponent oxides, represent another exciting, but only lightly explored opportunity for PLD. In contrast, tribological materials are typically neither complex nor multicomponent. Nevertheless, interesting structures and properties have been produced by PLD. A few of the more important ones will be discussed. These different types of materials demonstrate the diversity of capabilities offered by PLD.