Studies on dielectric and electrical properties of Ruddlesden-Popper oxide Sr_2SnO_4

摘要

Ruddlesden Popper (RP) oxide Sr_2SnO_4 has been synthesized via a solid state reaction route by calcination at 1000 ℃ for 8 h. The Rietveld refinement of X-ray diffraction (XRD) pattern suggested tetragonal structure; 14/mmm space group and unit cell parameters a = b = 4.05084(5) A, c= 12.59040(2) A. Dielectric properties, electric modulus and ac conductivity have been studied as a function of both frequency (20 Hz-2 MHz) and temperature (70-600 ℃) in air atmosphere. Dielectric constant and dissipation factor remains constant upto 600 ℃ above 1 KHz. AC conduction mechanism has been explained using Johnscher's Power law. The value of the activation energy for conduction, E_(cond) (obtained from DC conductivity) and dielectric relaxation, E_(relax) (obtained from modulus) is found to be the same indicating similar mechanism for both the processes. Based on the numerical value of activation energy, the conduction and relaxation processes are attributed to transfer of electron from Sn~(2+) to Sn~(4+) through the thermally assisted quantum mechanical tunneling process.