Electrical properties of La_0.67Ca_0.33Mn_0.99Fe_0.01O₃ colossal magnetoresistive composition under pressure

In this paper we report results of the electrical resistivity of colossal magnetoresistive composition under La^0.67Ca^0.33Mn^0.99Fe^0.01O³ colossal magnetoresistive composition under hydrostatic pressure up to 10 kbar. With the decrease in temperature the resistivity, under different pressures, undergoes a change in curvature at some temperature (T_I) corresponding to point of inflexion and then shows metal-insulator (MI) transition. At zero pressure, T_I is found to be 256.5 K whereas the temperature T_M corresponding to the intersecting point of the extrapolations of metallic and insulating regions is observed to be 234.1 K. The values are found to increase with increasing pressure. The derivatives dT_M/dP and dT_I/dP are observed to be 0.50 K/kbar and 0.67 K/kbar respectively. The analysis of resistivity data below is done using T_M is done using empirical relation ρ = ρ₀ + ρ₁Tⁿ and the data above T_M has been analysed using two existing models, Mott's variable range hopping (VRH) model and spin polaronic conduction (SPC) model. PACS 62.50.+p, 071.30.+h, 72.10.Bg, 74.72