Anomalous Behavior Of Electrical Resistivity Research Articles

My research life about titanium and its alloys; from investigation about anomalous behavior of electrical resistivity to development of low cost beta type titanium alloys

My research life about titanium and its alloys; from investigation about anomalous behavior of electrical resistivity to development of low cost beta type titanium alloys

Low temperature resistivity anomalies in bismuth doped manganites

With a view to understand the low temperature resistivity behaviour, especially below their metal insulator transition temperature, a series of bismuth doped lanthanum strontium manganites with compositional formula, La 0.67− x Bi x Sr 0.33MnO 3 (where x = 0, 0.1, 0.2, 0.3) were prepared by the sol–gel method. After characterizing these materials, a systematic investigation of electrical resistivity both as a function of temperature and magnetic field was undertaken. It has been found that the electrical resistivity of all the samples exhibits an upturn at about 30 K in the ferromagnetic region ( T < T C). The anomalous behaviour of electrical resistivity in the low temperature region was explained by a theory based on Kondo-like spin dependant scattering, electron–electron, electron–phonon and electron–magnon scattering. The high temperature electrical resistivity behaviour ( T > T P) was explained using adiabatic small polaron model.

Anomalous behavior of electrical resistivity in NdFe 11 Ti

The electrical resistivity, ϱ, and temperature derivative of resistivity (d/dT) of polycrystalline NdFe11Ti are investigated. The resistivity exhibits an anomalous behavior at about 160 K and 220 K. These anomalies attributed to spin reorientation phenomena originate from two magnetic phase transition. A modified theoretical model for electrical resistivity, ϱ and dϱ/dT, behavior in the spin reorientation temperature (TSR) region is presented. The results suggest that the average magnetic moment at TSR1 ∼ 160 K is aligned along a cone angle and at TSR2 ∼ 220 K along c-axis. The temperature dependence of ac-susceptibility, χac(T), is presented. The results show the existence of the spin reorientation related to a magnetic phase transition. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Anomalous behavior of electrical resistivity in glass transition region of a bulk Pd 40Ni 40P 20 metallic glass

The electrical resistivity of a bulk Pd 40Ni 40P 20 metallic glass was measured as a function of temperature. This glass showed a positive slope, dρ/ dT=(1.28±0.03)×10 −4 μΩ m/K, with a residual resistivity ρ 300 of 1.29±0.03 μΩ m at room temperature. Also, the change in the resistivity due to the glass transition was carefully investigated, but, no variation in the neighborhood of glass transition temperature was observed. Bulk glasses Pd 40Cu 3Ni 37P 20 and Pd 43Ni 37P 20 with slightly different composition were also prepared for a comparison. In case of these glasses, the slope, d ρ/d T, varied at the glass transition, i.e. the resistivity decreased after the glass transition for the former and increased for the latter. The slope of the resistivity curve measured for the Pd 40Ni 40P 20 melt was larger than that of the glass. Thus, the extrapolated resistivity to higher temperature did not connect smoothly with the resistivity of the liquid phase.

Electrical resistivity and entropy of mixing of liquid lithium-lead and sodium-lead alloys

The complex formation model is used to explain the anomalous behaviour of electrical resistivity and entropy of mixing of Li-Pb and Na-Pb liquid alloys as a function of concentration. The interionic pairpotentials (φ ij ) are evaluated within the framework of the pseudo-potential theory which in turn is used to obtain the values for hard sphere diameters (σ i ) of Li, Na and Pb in the alloys. The study reveals that the constituent metals of these alloys undergo major structural changes in atomic and electronic character on alloying. The concentration dependent anomaly in electrical resistivity and entropy of mixing occurs due to preferential ordering of unlike atoms as nearest neighbours which could simultaneously be understood in Li-Pb and Na-Pb liquid alloys with the help of the complex formation model.

Anomalous behaviour of electrical resistivity in FeMnAl alloys

The anomalous behaviour of resistivity in bulk polycrystalline FeMnAl alloys is presented. The minimum in the ϱ( T) curve at low temperature is due to the Kondo-like behaviour induced by sufficient Al. The minimum at high temperature is due to the magnetic phase transition, that is, from paramagnetism to antiferromagnetism of gap type.

Anomalous Behavior of Electrical Resistivity in the Alloys with High Concentration of Magnetic Atoms

Anomalous Behavior of Electrical Resistivity in the Alloys with High Concentration of Magnetic Atoms