Critical Behaviour Of Electrical Resistivity Research Articles

Critical behavior of electrical resistivity in amorphous Fe-Zr alloys

Electrical resistivity (ρ) of the amorphous (a-)Fe100−c Zr c (c=8.5, 9.5 and 10) alloys has been measured in the temperature range 77 to 300 K, which embraces the second-order magnetic phase transition at the Curie temperature point T c. Analysis of the resistivity data particularly in the critical region reveals that these systems have a much wider range of critical region compared to other crystalline ferromagnetic materials. The value of T c and specific heat critical exponent, α has the same values as those determined from our earlier magnetic measurements. The value of α for all the present investigated alloys are in close agreement with the values predicted for three-dimensional (3D) Heisenberg ferromagnet systems, which gives contradiction to the earlier results on similar alloys. It is observed from the analysis that the presence of quenched disorder does not have any influence on critical behavior.

Effect of Interfacial Polarization on the Critical Behaviour of Electrical Resistivity and Dielectric Constant in Polar + Nonpolar Binary Liquid Mixtures

AbstractThe dielectric constant ϵ and the resistance R have been measured as a function of frequency in the region 1 kHz to 1 MHz. The measurements have been performed on two critical binary liquid mixtures cyclohexane + methanol and carbondisulphide + acetonitrile in the one phase region. The measurements are carried out using a double ratio transformer bridge, in a bath with millidegree temperature control. At low frequencies ϵ and R increase with T → Tc+. Above 100 kHz the resistance reaches a maximum and begins to decrease as T → Tc+. The observed behaviour is explained qualitatively on the basis of interfacial polarization mechanisms (IPM) using the ideas of the droplet model theory of binary Liquid mixtures. The analysis of the low frequency data using the functional form R or ϵ ˜ tθ shows a value of θ near 0.9. The high frequency data have been analysed with a new functional form, but the quantitative discussions of the IPM are hampered by the lack of information of its dependence upon t.

Critical behavior of electrical resistivity in polar + nonpolar binary liquid systems

The behavior of electrical resistivity in the critical region of three polar + nonpolar binary liquid systems CS2 +(CH3CO)2O, C6H12+(CH3CO)2O, and n-C7H16+(CH3CO)2O is studied. For the mixtures with critical composition, the two phase region shows a conductivity behavior with σ1−σ2∼ (−ε)β with β?0.35. In the one phase region dR/dT has a singularity ε−b with b?0.35. A possible theory of the impurity conduction is given, which broadly explains these results. The possibility of dR/dT being positive or negative is also discussed.

Critical behaviour of electrical resistivity in 5 binary liquid systems

For five binary liquid systems CS 2+CH 3CN, CS 2+CH 3NO 2, CS 2+(CH 3CO) 2O, C 6H 12+(CH 3CO) 2O, n-C 7H 16+(CH 3CO) 2O, the electrical resistance has been measured near the critical solution temperatures. The behaviour is universal. Below T c, the conductivities of the two phases follow ∣ σ 1− σ 2∣∼ ϵ β , where ϵ=∣ T− T c∣ T c with β≈0.35. In the one phase region dR dT ∼ϵ -b with b≈0.35±0.1 and dR dT is positive in some cases and negative in others.