impact of nano-micro particle size on structural, magnetic and electrical properties of la0.5ca0.5mno3 manganites

Structural, magnetic, and electrical properties of la0.5ca0.5mno3 samples prepared at two different sintering temperatures (800°c and 1350°c which were labeled s800 and s1350, respectively) have been investigated. the reitveled refined xrd patterns indicate an orthorombic structure with pnma space group for both samples. ac susceptibility measurements show that, the fraction of ferromagnetic and antiferromagnetic phases could be controlled with sintering temperature. s800 sample has a ferromagnetic state while the antiferromagnetic phase is enhanced in s1350 sample which causes the increase of thermal hysteresis in this sample. two distinct regions (t>өd/2 and t˂өd/2, өd is the debye’s temperature) were noticed to investigate the electrical properties. based on the resistivity data at t>өd/2 region, the s800 and s1350 samples follow the adiabatic and non adiabatic small polaron hopping (sph) models, respectively. at t˂өd/2 region, the 3-dementional variable range hopping (vrh) model displays a good correlation with the experimental data of both samples. the related parameters of both sph and vrh models are extracted. the results show that these parameters are particle size dependent.