ELECTRICAL AND STRUCTURAL PROPERTIES OF CaMnO - Y CERAMIC COMPOUNDS

By using the solid-state reaction method samples of Ca1-xYxMnO3 CaMnO-Y were prepared. Transport properties of the samples were studied from electrical resistivity rho(T) and Seebeck coefficient ST measurements. The structural and morphological properties were researched by X-ray diffraction analysis and scanning electron microscopy SEM, respectively. The Seebeck coefficient is negative throughout the studied temperature range indicating a conduction given by negative charge carriers. The magnitude of ST decreases with the yttrium level, which suggest an increase in the charge carrier density. The temperature behavior of electrical resistivity exhibit a semiconducting character; the magnitude of rho(T) decreases with yttrium level reaching minimum values close to 0.5 mu cm. From the electrical resistivity and Seebeck coefficient experimental data it was possible to calculate the thermoelectric power factor, which shows maximum values around 0.12W-K(2)cm., Utilizando el metodo de reaccion de estado solido se prepararon muestras del compuesto Ca1-xYxMnO3 CaMnO-Y. Sus propiedades de transporte se estudiaron a partir de mediciones de resistividad electrica rho T y coeficiente Seebeck ST, en funcion de la temperatura y el contenido de itrio. Por medio de analisis de difraccion de rayos-X y microscopia electronica de barrido SEM se estudiaron las propiedades estructurales y morfologicas, respectivamente. El coeficiente Seebeck es negativo en todo el rango de temperatura estudiado sugiriendo una conduccion dada por portadores de carga negativos. La magnitud de ST decrece con el nivel de itrio presente, evidenciando un incremento en la densidad de portadores de carga. El comportamiento de la resistividad electrica es de caracter semiconductor y su valor minimo a temperatura ambiente es cercano a 0.5 Omega cm. Utilizando los datos experimentales de resistividad electrica y coeficiente Seebeck se calculo el factor de potencia termoelectrico cuyo maximo valor a temperatura ambiente fue cercano a 0.12 mu W/K(2)cm.