Design and construction of a pulsed high magnetic field facility and high field magnetoresistance studies in some semiconductors

Abstract

Negative magnetoresistance at 77?K saturates to a value of 0.04 to 0.06 and shows anisotropic behavior. In this connection, a critical review of the experimental results and the theoretical models of negative magnetoresistance has been made, and the results have been examined in the light of available models. The high-field magnetoresistance studies in several samples of p-type lead telluride have been extended up to a peak field of 20?T, corresponding to a non-dimensional parameter of 20. The magnetoresistance data indicates a definite saturation at higher fields. The magnetoresistance data at saturation has been analyzed to yield information on the total anisotropy ratio K?. The data favors a value of K? = 4.8. The difference between K? and the effective mass ratio K, as obtained from cyclotron resonance measurements, has been examined, taking into account factors such as polar and acoustic scattering. The magnetoresistance data at high fields is compared with Gold-Roth theory. Keywords: High magnetic fields, Tesla, Thyristors, Search coils, Co-axial current shunts, Negative magnetoresistance, Inhomogeneity effects, High-field magnetoresistance, Anisotropy ratio, Scattering. polar optical and acoustic.