Effect of Bi addition on dc, ac conductivity and dielectric properties of Te15(Se100-xBix)85 glassy alloys

Abstract

The present paper reports the dc, ac conductivity and dielectric properties viz. dielectric constant and dielectric loss of Te15(Se100-xBix)85 (x=0, 1, 2, 3, 4 at.%) glassy alloys at room temperature. The dc conductivity is calculated from the I-V characteristics curves of the pellets of bulk samples prepared by melt quenching technique. The samples obey Ohm’s law in the lower (0-25V) voltage range whereas the behaviour in the higher (25-100V) voltage range is non-ohmic. The experimental results indicate that the conduction mechanism in these samples in the higher voltage range is Poole-Frenkel type. The increase in dc conductivity is probably due to Se-Bi bond concentration in the Se-Te-Bi glasses. The experimental results indicate that ac conductivity and the dielectric properties of the bulk samples are frequency dependent. The ac conductivity is found to obey the s law. This increase in ac conductivity is probably due to relaxation caused by the motion of electrons or atoms. The ac conductivity is further found to increase with Bi content. The dielectric constant and dielectric loss are found to decrease with frequency and increase with Bi content.