Studies of transport properties of RFe_(1-x)Ni_xO _3 (x ≤ 0.5) WHERE R = Nd, Sm and Gd

摘要

We present here the electrical transport properties of RFe _(1-x)Ni_xO_3 (x ≤ 0.5) where R = Nd, Sm and Gd and the correlation between these systems. The resistivity increases as the rare ion is changed from Nd to Sm. The resistivity increases from the magnitude of the order of 103 to 106 Ωcm at lower temperatures and from 10 to 105 Ωcm as the temperature is increased. Also, the resistivity decreases as the concentration of Ni is increased within the ensemble showing a semiconducting behavior. The resistivity data is fitted with the Greaves Variable Range Hopping model which fits in the intermediate range of temperatures. There is decrease in gap parameter, increase in conductivity and increase in the density of states at Fermi level which clarify that the correlation length in the conducting network increases with the increase in Ni substitution. The Debye temperature decreases as the Ni concentration increases and follows the same trend as the rare earth ion is replaced.