CONICET | Buscador de Institutos y Recursos Humanos

Capacitor is the most widely used component in modern electronic devices. A large number of MLCCs (multi-layer ceramic capacitors) are manufactured annually. In these applications, BaTiO3 is used as a base material and is considered as the cornerstone of electroceramics market [1]. X9R like capacitors require a temperature stable capacitance with ±15% variation over the temperature range -55 to 200oC [2]. BaTiO3-BiMg0.5Ti0.5O3 has been reported to exhibit temperature stable permittivity at higher temperatures (> room temperature) [3]. Therefore, an attempt was made to decrease the operating temperature of BaTiO3-BiMg0.5Ti0.5O3 via NaNbO3 addition [4]. Consequently, in the present study, we have investigated 75BaTiO3-(25-x)BiMg0.5Ti0.5O3-xNaNbO3 (0.05≤x≤0.20) via mixed oxide solid state route where reactants where mechanochemically activated. Activated powders were calcined at 950 for 4 hours. Finally, the obtained powders were uniaxially pressed and sintered at 1150 °C for 4 hours. Sintered samples were characterized through X-Ray Diffraction patterns (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), and dielectric properties (dielectric permittivity and dielectric loss) in the temperature range -80°C to 500°C. The XRD patterns of the samples showed the formation of cubic structure. No evidence of secondary phases was found within the detection limit of in-house XRD facility which was in agreement with the Raman spectra of the samples. Microstructural analysis of the samples exhibited dense pack grain morphology. Relative permittivity and dielectric loss as a function of temperature for the sample with x = 0.10 showed a temperature stable relative permittivity of ~ 840 ± 15% over the temperature range -62 to 200 oC and dielectric losses < 0.02 in a wide temperature range (-28 to 374 oC). The temperature stable relative permittivity suggests that the materials is promising candidate for X9R type capacitors.