The high-temperature conductivity of the perovskite oxides of a LaBaCuO (LBCO) thin film prepared by RF sputtering deposition and thermal annealing has been studied. While the bulk LBCO compound was metallic, the LBCO film deposited on a Si substrate by sputtering and a post annealing process showed semiconductor-like conduction, which is considered to be due to the defects and poor grain connectivity in the LBCO film on the Si substrate. The LBCO film deposited on a SrTiO substrate was of high film quality and showed metallic conduction.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
April 2021
Sr[AlO](SO) (SAS) and Ca[AlO](SO) (CAS) are members of the aluminate sodalite-type oxides with the general chemical formula M[AlO](XO) (M is the guest cation and XO is the guest anion). To discuss the role of the guest cations (M = Sr and Ca) on the rotation of AlO in the oxygen tetrahedral framework in the I43m phase, the crystal structure parameters and the probability density function of the guest ions in SAS and CAS have been investigated via synchrotron radiation X-ray powder diffraction by considering Gram-Charlier expansions. The interatomic distances between the M and O ions evaluated from the maximum positions in the probability density distribution are almost equal to the sum of the ideal ionic radii of the M and O ions.
View Article and Find Full Text PDFThe NaCoCuO thick film with the same thermoelectric performance as a NaCoO bulk was formed on an alumina substrate by the screen-printing process. The power factor exceeded 0.3 mW/Km, with the resistivity of 3.
View Article and Find Full Text PDFWe investigated the Co substitution effect for the magnetic properties in room-temperature ferromagnetic oxide SrYCoO. The substituted element (Al and Ga) and low-spin state Co, which was changed from a high-spin or intermediate-spin state by Al or Ga substitution, reduced the Curie temperature to even 1.5 times lower than the temperature estimated from a simple dilution effect.
View Article and Find Full Text PDFStructural phase transitions of calcium strontium sulfoaluminate series, (CaSr)[AlO](SO) ((CS)AS-) with = 0.80-1.00, are systematically investigated by powder X-ray diffraction, dielectric measurements, and pyroelectric measurements, to clarify a phase diagram of (CS)AS- ( = 0.
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