Correlation between magnetic and electric properties based on the critical behavior of resistivity and percolation model of La_0.8Ba_0.1Ca_0.1MnO₃ polycrystalline

Abstract

We investigated the magneto-electrical properties of a La0.8Ba0.1Ca0.1MnO3 polycrystalline sample, prepared by the polymerization-complex sol–gel method.

Electrical conductivity and dielectric behaviour of nanocrystalline La0.6Gd0.1Sr0.3Mn0.75Si0.25O3

“…The effect of substituting Mn by Ga, Ru, Fe, Co, Cr and Ti is well studied. [9][10][11][12][13][14] The physical properties are successfully explained by a doubleexchange (DE) mechanism based on a strong exchange interaction between Mn 4+ and Mn 3+ ions through intervening lled oxygen 2p states. It is believed that the interaction between the pairs of Mn 4+ and Mn 3+ ions is responsible for the electrical properties in these manganese oxides.…”

Spin-polarized tunneling and polaronic transport properties of polycrystalline (Sm1−y Gd y )0.55Sr0.45MnO3 (y = 0.5 and 0.7) compounds

“…(Sm delocalization of electrons facilitates the easy hopping of the electrons to the nearby neighboring states [44,46,47]. The estimated values of θ D as obtained from the ln(ρ/T) vs 1/T plots for both the compounds increase with increasing the strength of magnetic fields.…”

“…In our case, we did not observe any such kind of linearity in log ρ vs 1/T plot, suggesting the rejection of the band gap model to describe the conduction mechanism in the present studied systems. Alternatively, one can use two different models viz small polaron hopping (SPH) and variable range hopping (VRH) models in the two different sections of the resistivity data above T MI [44][45][46][47][48][49]. The SPH model is applicable when the thermal energy is not enough high to overcome the deep potential well where electrons are trapped.…”

“…The thermal energy received by any second phonon helps to hop out that electron from the intermediate state to its nearest neighbor state easily [28]. According to the SPH model, the expression for the resistivity is given by the relation, ρ = AT exp(E P /k B T), (7) where 2αR), E P is the activation energy for the polaronic hopping process of conduction electrons, k B is the Boltzmann constant, N is the number of ion sites per unit volume, R is the average inter-site spacing calculated from the relation R = (1/N) 1/3 , C is the fraction of sites occupied by a polaron, α is the electron wave function decay constant and ν ph is the optical phonon frequency having the expression ν ph = k B θ D /h, θ D is the Debye temperature [44]. The value of θ D /2 can be estimated from the temperature at which a deviation from the linearity starts in the ln(ρ/T) vs 1/T plot as shown in the inset of figure 6(a) as a representative [44,45].…”

“…Due to the variation of hopping range for this loosely trapped electrons, it is called VRH. In case of the three dimensional system, the VRH model for resistivity [42,44,46] can be expressed as…”