2 research outputs found
ElektriÄna i termoelektriÄna svojstva Äistog i supstituiranih bakrenih ferita
Samples of the CuFe2-xAlxO4 system with x=0, 0.2, 0.4 and 0.6 were prepared. The single phase spinel structure was verified by X-ray diffraction method. The thermoelectric power (a) and dc electrical resistivity (r) were studied as a function of temperature and composition. The results show that the resistivity increases and the transition temperature decreases with increasing the aluminium substitution. The activation energy in ferrimagnetic region is lower than that in paramagnetic region. The drift mobility of carriers increases exponentially with temperature as expected for ferrites.PrireÄeni su uzorci sistema CuFe2āxAlxO4 sa x = 0, 0,2, 0,4 i 0,6. ProuÄavana je termoelektriÄna sila i dc elektriÄna otpornost u ovisnosti o temperaturi i sastavu. Rezultati mjerenja pokazuju da se otpornost poveÄava a temperatura prijelaza smanjuje sa poveÄanjem koncentracije aluminija. Aktivacijska energija veÄa je u feromagnetskoj nego u paramagnetskoj fazi. U skladu s oÄekivanjem, ustanovljeno je da se mobilnost nosilaca naboja u feritima eksponencijalno poveÄava s temperaturom