Electronic, magnetic and thermal properties of Pb₂₋x AxCrO₅ (A = K or La)
Abstract
Lead chromium oxide is a photoconductive dielectric material tha t has great potential
of being used as a room temperature photodetector. In this research, we made ceramic pellets of this compound as well as potassium doped compound Pb2-xKxCr05,
where x=O, 0.05, 0.125. We also investigate the properties of the lanthanum doped
sample whose chemical formula is Pb1.85Lao.15Cr05' The electronic, magnetic and thermal properties of these materials have been studied. Magnetization measurements of the Pb2Cr05 sample indicate a transition at about 310 K, while for the lanthanum doped sample the transition temperature is at about 295 K indicating
a paramagnetic behavior. However, the potassium doped samples are showing the
transition from paramagnetic state to diamagnetic state at different temperatures
for different amounts of potassium atoms present in the sample. We have studied
resistivity as a function of temperature in different gas environments from 300 K to
900 K. The resistivity measurement of the parent sample indicates a conducting to
insulating transition at about 300 K and upon increasing the temperature further,
above 450 K the sample becomes an ionic conductor. As temperature increases a
decrease in resistance is observed in the lanthanum/potassium doped samples. Using
Differential Scanning Calorimetry experiment an endothermic peak is observed for
the Pb2Cr05 and lanthanum/potassium doped samples at about 285 K.