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La0.75Sr0.25MnO3 particles were synthesized by ultrasonic spray pyrolysis at synthesis temperatures of 1173, 1273, and 1473 K, a reaction time of 9.4 S, and a source solution concentration of 0.5 mol L−1. The particles produced generated heat in the AC magnetic field, and particle temperature increased quickly with time, attaining constant Thmax values of 312, 327, and 353 K. These Thmax values enclosed the temperature range for hyperthermia (316–318 K). Their Curie temperatures Tc evaluated were 314, 329, and 358 K. Thmax increased linearly with increasing Tc and the values obtained were almost similar to Tc.

The cluster-ion deposition method was newly developed here based on the ionization chemical vapor deposition (ionization CVD) method. In this new method, reactant gases are first ionized and then form cluster ions that deposit directly onto a substrate. Experimental results revealed that (1) SiO2 nanoparticles can be deposited on Si wafers at temperatures lower than the particle generation temperature in tetraethylorthosilicate (TEOS)/oxygen reaction system, (2) the Si wafer (1.4 ×1.4 cm2) can be uniformly covered with nanoparticles at high density (1010 cm-2), and (3) nanoparticles can be selectively deposited and arranged onto a charged line pattern on the Si wafer.

A new chemical vapor deposition (CVD) method called ionization CVD, where source molecules were ionized and deposited on a substrate by Coulombic forces in an electric field, was proposed. Film formation from tetraethylorthosilicate (TEOS)/ozone CVD was used to demonstrate this method. Film-growth rates increased linearly with increasing electric fields from 0 to 1.67 kV· cm-1. The FT-IR spectra of the resulting films showed they were composed of SiO2. It was found that 60% of the intermediates had a negative charge and that the electric field required to deposit them was lower than 1.67 kV· cm-1.

In order to clarify the mechanisms of film formation in an atmospheric-pressure chemical vapor deposition reactor using the tetraethylorthosilicate/O3/He system, the contents of C, H, and SiO2 in the intermediate species were estimated from both CHN elemental chemical component and thermogravimetric analyses of simultaneously generated nanometer-sized particles. From the results of compositional analysis of intermediate species and SEM observation of resultant films, the intermediate species which form films with excellent flow-like shape were found to contain relatively large amounts of ethoxy group and small amounts of hydroxyl group.

Film formation on a substrate and particle generation in the gas phase were examined simultaneously in an atmospheric-pressure chemical vapor deposition (CVD) reactor using tetraethylorthosilicate(TEOS)/O3/He, TEOS/O2/He and TEOS/He systems. Particle generation in these systems began at furnace temperatures T f of 60, 340 and 740°C, respectively. Film formation began at T f=100, 600 and 700°C, respectively. For the TEOS/O3/He system, an exponential reduction in the film growth rate for T f≥300°C was found to be induced by a decrease in the ozone concentration due to thermal decomposition.

The structure of nano-phase silver particles was investigated by fluorescence EXAFS over several sizes of particles. The particle concentrates (>1021part./m3) were prepared using the aerosol process associated with surfactant coating to maintain the isolation of each particle. The EXAFS of the particles showed a good signal-to-noise ratio even in the particles less than 3 nm in diameter. The nearest neighbor distances of silver atom in the particles and foil were 0.289 (±0.002) nm for all the cases, and no distinct shrinkage of the atomic distance was observed for the silver particles in the size range of this work.

Formation of a SiO2 film on a substrate and generation of particles in the gas phase were examined simultaneously in an atmospheric-pressure chemical vapor deposition (APCVD) process using tetraethylorthosilicate (TEOS). The furnace temperature range where SiO2 films can be prepared without particle generation was found to be 700-740°C. The particles generated from the APCVD process were spherical, amorphous, and had a diameter smaller than 60 nm. The Fourier transform infrared and thermal desorption spectra showed that the particles contained a small amount of an ethoxy group and a relatively large amount of a hydroxyl group.

Direct observation of 18O tracer diffusion by secondary ion mass spectrometry (SIMS) was made on a single crystal of YBa2Cu3O y with an array of steps on the stairlike surface. The unique distribution of the diffused 18O in the ab-plane and in the c-axis direction was shown visually as a mapped image, which revealed some fundamental processes on the oxygen penetration through the surface and diffusion in the inner crystal. It was found that at 530°C, the diffusion coefficient in an ab-plane is larger than that in a c-axis direction by more than five orders of magnitude.

High-T c superconducting thick films were prepared using fine powders obtained by spray pyrolysis. The 110 K phase was predominantly formed in the films heat-treated at 855°C. The films prepared using fine powders with an average particle size of 1.4 µm showed a higher T c(zero) of 105 K compared with those using powders of 0.8 µm.

Fine powders of the compound YBa2Cu3O7-x have been prepared directly by the spray-pyrolysis of aqueous solutions of corresponding metal nitrates. The powders obtained in a temperature range of 900 to 1000°C were spherical and their diameters were uniformly distributed below 1 µm. The crystallinity of these powders was increased with increasing decomposition temperature; an orthorhombic single phase was indeed obtained at 1000°C. The sintered bodies from these powders showed the offset of superconducting transition at 84 K.