La0.7-xCexSr0.3MnO3 specimens were fabricated by a solid state reaction method and structural and electrical properties with variation of Ce4+ contents were measured. All specimens exhibited a polycrystalline rhombohedral crystal structure, and the (110) peaks were shifted to low angle side with increasing the amount of Ce4+ contents. As Ce4+ ions with different ion radii and charges are substituted with La3+ ions, electrical properties are thought to be affected by changes in the double exchange interaction between Mn3+-Mn4+ ions due to distortion of the unit lattice, a decrease in oxygen vacancy concentration, and an increase in lattice defects. Resistivity gradually decrease as the amount of Ce4+ added increased, and negative temperature coefficient of resistance (NTCR) properties were shown in all specimens. In the La0.5Ce0.2Sr0.3MnO3 specimens, electrical resistivity, TCR and B-value were 31.8 Ω-cm, 0.55%/℃ and 605 K, respectively.
Conductive SrMoO3 thin films were fabricated by RF magnetron sputtering with the powder-type sputtering target, and annealed for crystallization. When RTP (rapid thermal processing) in vacuum was applied, the fabricated thin films showed the mixed phases of SrMoO3 and SrMoO4, but SrMoO3 phase could be promoted by the lowering of the working pressure during deposition. In order to eliminate O2 gas during deposition and annealing, further lowering of the working pressure and furnace annealing in hydrogen atmosphere were tried. With the optimization of the deposition and annealing conditions, the thin film with nearly single-phase of SrMoO3 was obtained, and it showed good electrical conduction properties with a low resistivity of 2.5×10(-3)Ω·cm at room temperature.
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Conductive single-phase SrMoO
3
epitaxial films synthesized in pure Ar ambience via plasma-assisted radio frequency sputtering
Mouli Roy-Chowdhury, Cong He, Ke Tang, Hiroki Koizumi, Zhenchao Wen, Subhash Thota, Hiroaki Sukegawa, Tadakatsu Ohkubo, Seiji Mitani Science and Technology of Advanced Materials.2024;[Epub] CrossRef