Thin films of antiperovskite Mn3GaN1-x were grown on MgO (001) substrates by reactive magnetron sputtering, and their structural, magnetic, and magneto-optical properties were systematically investigated. It was found that the combination of the deposition rate and the N2 gas partial pressure could produce epitaxial films with a wide range of N composition (N-deficiency) and resulting c/a values (0.93 - 1.0). While the films with c/a = 0.992 - 1.0 were antiferromagnetic, the films with c/a = 0.93 - 0.989 showed perpendicular magnetic anisotropy (PMA) with the maximum PMA energy up to 1.5×106 erg/cm3. Systematic dependences of the energy spectra of the polar Kerr signals on the c/a ratio were observed, and the Kerr ellipticity was as large as 2.4 deg. at 1.9 eV for perpendicularly magnetized ferromagnetic thin films with c/a = 0.975. These results highlight that the tetragonal distortion plays an important role in magnetic and magneto-optical properties of Mn3GaN1-x thin films.

Preparation of CaO core-SiO 2 shell nanoparticles as a chemical thermal storage through hydration/de-hydration of CaO/ Ca(OH) 2 was proposed. Firstly, SiO 2 was coated on CaCO 3 template surface using solgel route and then the coreshell particles were heated at 700°C to form CaO@SiO 2 nanoparticle by de-carbonization. A thermal storage performance of the CaO@SiO 2 was confirmed by a thermogravimetry (TG) analysis and the result was compared with that of as-received CaCO 3 . The heating program was performed as following steps as (i) at 700°C for 30 min for de-carbonization under nitrogen (N 2 ) atmosphere, (ii) at room temperature for 60 min for hydration under water vapor, and (iii) at 500°C for de-hydration under N 2 . By repeating of (ii) hydration/(iii) de-hydration cycle, effect of the number of cycles on thermal storage ability was investigated. An efficiency of thermal storage was defined as difference in weight change between hydration/de-hydration reactions. For the as-received CaCO 3 nanoparticles, with increase in the number of cycles, the thermal storage performance gradually decreased. The microscopic results showed that the heating cycles induces coalescence of CaCO 3 nanoparticles and that decreases specific surface area. On the other hands, efficiency of thermal storage of CaO@SiO 2 didn't reach theoretical value because CaCO 3 didn't completely transform into CaO owing to SiO 2 's thermal insulation ability. By decreasing SiO 2 coating thickness, the thermal storage performance of CaO@SiO 2 was improved. The microscopic results showed that the SiO 2 coating prevented from coalescence of CaCO 3 nanoparticles.

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We report the first real time, in situ synchrotron x-ray studies of Y-Ba-Cu-O thin-film growth on (100) SrTiO3 using a miniature, faced-magnetron sputtering system. A combination of the substrate temperature and the deposition rate determines whether the film grows along the a, c, or multiple axes.

We report what we believe to be the first real time, insitu studies of film growth by sputtering using synchrotron Xrays; the structure and growth habit of YBa&u,O? (YBCO) thin films deposited on (100) SrTiO, in a mimature, facedmagnetron sputtering system have been investigated. A combination of the substrate temperature and the deposition rate determines whether the film grows along the a, c or multiple axes. At low substrate temperatures and low deposition rates, the films grow preferentially along the a-axis. In contrast, higher substrate temperatures and high deposition rates favor c-axis oriented film growth with some admixture of (220). The X-ray diffraction peaks were monitored in real time revealing that both a-axis and c-axis oriented grains nucleated on the surface of the (100) SrTiO, between 625" and 765" C, although the volume fraction of each orientation was temperature dependent. The structural quality of the a-axis films is superior to that of the c-axis films. The best a-axis films (deposited at 685" C), had a rocking curve width of 0.08", which is 10 times smaller than that for the c-axis films (deposited at 800" C). We have observed a shift of the (007) and (200) peak positions during deposition. The shift in the (007) peak is larger than that for the (200) peak. Defects in the c-axis films were observed, not only at the interface between the film and the substrate, but also on the upper surface of the (final) film; the latter seems to be inherent and is more severe in our films.