Department of Physics, T.D.P.G. College, Jaunpur UP India

Email:-ant_tdc@yahoo.com

 This paper reports the measurement of dielectric (K), electrical Conductivity (s) and Seebeck coefficient (S) of terbium orthochromite in the temperature range of 350 to 1000K. TbCrO₃ is a large dielectric constant material with K values of 316 at 10²Hz and 100 at 10³ Hz at 350K. The logK vs T plot is not smooth but shows anamolies at 446K and 755K, the latter has been interpreted as a phase transition of the material. Above 1000K the value of dielectric constant starts decreasing with temperature which is a typical characteristic of ferroelectric materials. The log sT vs T^-1 as well as S vs T^-1 plots show four distinct linear regions in the temperature intervals of 384- 444K, 444-714K, 800-1000K and 1000-1100K. The S values are positive and constant in these temperature intervals but log sT vs T^-1 plot has slopes of 0.34 eV, 0.48 eV, 0.73 eV and 0.73 eV in the four temperature ranges. It has been concluded that intrinsic band conduction is not the mechanism of electrical conductivity but it occurs due to hopping of electrons from Cr³⁺ to Cr⁴⁺ centres. These Cr⁴⁺ centres are created due to native defects. The number of these centres as well as the resulting Seebeck coefficient have also been calculated. The latter has a good agreement with the experimentally observed values.