New powellite type oxides in Ca–R–Nb–Mo–O system (R=Y, La, Nd, Sm or Bi)—Their synthesis, structure and dielectric properties
2008; Elsevier BV; Volume: 62; Issue: 17-18 Linguagem: Inglês
10.1016/j.matlet.2008.01.116
ISSN1873-4979
AutoresK. Ravindran Nair, P. Prabhakar Rao, S. Sameera, Vinitha S. Mohan, M.R. Chandran, Peter Koshy,
Tópico(s)Nuclear materials and radiation effects
ResumoAbstract New complex oxides having powellite (CaMoO4) type structure in the Ca–R–Nb–Mo–O system (R = Y, La, Nd, Sm or Bi) were prepared employing the method of solid state reaction between the component oxides at high temperature (1000–1100 °C). The new compounds, CaRNbMoO8 (R = Y, La, Nd, Sm, Bi) are colorless and electrical insulators. The dielectric constants (K at 1 MHz) of these compounds are in the range 14–33 and K shows very little variation in the temperature range 30–100 °C. Their temperature coefficient of dielectric constant (TCK) is negative, which varies from − 21 to − 220 ppm/°C.
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