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Modified strontium barium niobate and lead potassium niobate ceramics with tungsten bronze structure were prepared by the conventional ceramic techniques. The effect of various dopants on the properties of strontium barium niobate ceramics have been investigated. Curie temperature decreases with the increase of the ionic radius of dopant. The properties of filled and unfilled structures are compared. The effect of La3+ on Lead Potassium Niobate is discussed.

A series of glass samples, according to the formula (100 − x) (0.5Li2O − 0.2Ga2O3 − 0.3P2O5) + xSeO2 (x = 0, 2, 4, 6, 8, 10) and 12 mol.%, labeled as LGPS x (x is the mole percent of SeO2), were synthesized through melt quenching technique. All the LGPS x samples were irradiated by a high energy proton (H+) beam of 3 MeV at fluence of 1014, 5 × 1014, and 10 × 1014 ions/cm2. FTIR and Raman spectra indicated that SeO2 acts either as a glass modifier (SeO 3 2− ) or a glass former (SeO 4 2− ), as the dose rate of beam fluence changes. The bulk conductivity of the highest conducting sample LGPS10 irradiated at a beam fluence of 5 × 1014 ions/cm2 was determined as 5.87 × 10−04 S/cm at 303 K. The super curve in the normalized spectra of electrical modulus at different temperatures confirms that the LGPS samples follow the temperature-independent, frequency-dependent relaxation time before and after irradiation.

Influence de l'introduction de Ag + et K + sur les proprietes ferroelectriques et piezoelectriques du niobate de plomb et de baryum

Modified Strontium Barium Niobate ceramics with tungsten bronze filled structure were prepared by the conventional ceramic techniques. The dielectric constant is measured at 1 MHz as a function of temperature. The ferroelectric transition temperature is considerably lowered by the introduction of rare-earth Nd3+. The dielectric constant is found to be lower in Lithium composition.