Effect of particles size on magnetodielectric, magnetoimpedance and electrical properties of LaFeO_3 nanoparticles

摘要

Effect of particles size on the behavior of magnetoimpedance, magnetodielectric and detailed electrical properties of structural characterized LaFeO3 nanoparticles prepared through chemical pyrophoric reaction' technique having particles size of similar to 21, 43 and 51nm have investigated. Dielectric constant of these nanoparticles gives the evidence of space charge polarization in the sample at lower frequency regime. Maximum magnetodielectric effect is obtained to similar to 61% at room temperature for particle size of similar to 21nm, which may be due to the large surface to volume ratio of this nanoparticles compared to other particles size attributing the enhancement of space charge polarization. The maximum value of magnetoimpedance is found to similar to 92% for similar to 21nm nanoparticle at room temperature. Magnetic field and frequency dependence room temperature magnetoimpedance are decreased with particles size of the nanoparticles. This behaviour has been explained through the light of classical electrodynamics, which reveals that this effect is depending on the magnetic field and ac signal frequency. Impedance spectroscopy is employed to study the electrical transport properties of the samples considering an equivalent circuit model for the effect of nanometric grain size. The electrical relaxation process of these materials is temperature dependent. Furthermore, ac conductivity curves follow the Jonscher's power law for electrical conduction process of the system through polaronic hopping.