Note on the Hall Potential Across an Inhomogeneous Conductor

Abstract

1023of Terrestrial Magnetism. The protons scattered from a thin carbon target on a silver leaf backing were counted with an argonfilled proportional counter biased to count only those protons near the end of their range. The ratio of the number scattered by carbon to the number scattered by silver determined the ratio of the cross sections except for a constant multiplying factor due to the difference in the number of carbon nuclei and silver nuclei. Since the ratio of cross sections was determined the target thicknesses were not determined, but both targets were thin; and since both targets were bombarded at the same time the geometrical factors cancel. The protons scattered from the two different nuclei can be resolved because of the difference of the recoil energy of the nuclei.Number vs. range curves were determined at 55°, 90°, 132.5°, and 160° in the laboratory system for bombarding energies of 2.5 and 2.75 Mev and at 90°, 132.5°, and 160° for energies of 2.0 and 2.25 Mev (Fig. 1). The area under a peak minus a fixed area determined by the channel width of the detecting system, which is a function of the effective counter and depth and the bias of the system, is proportional to the intensity. The channel width is defined here as the intercept of the curve of widths of the proton peaks at half-maximum vs. range in air at zero range. The slope of this curve is very nearly the slope of the range straggling curve computed for widths at half-maximum. 1 The area under the peaks was measured with a planimeter; several independent measurements were made for each area and the ratio of the average values was used.The half-widths due to straggling and channel width were assumed to add as the sum of the squares then the ratio of areas was corrected for channel width by multiplying by [(o-obs where a 0 bs is the observed width at half-maximum and a c h is the channel width. The ratio of the areas was also transformed to the carbon center-of-mass system, assuming that the silver scattering is classical.The corrected area ratios vs. angle in the carbon center-of-mass system are shown in Fig. 2. The dotted line is 2 R(<f>) at 2.5 Mev for 5-wave scattering, with 5 0 at 125° as determined by Heitler 2 ei al. y normalized to 0.1 at 60°. The error of ±10 percent consists principally of the statistical counting errors, errors in area measurement, and errors in measuring the widths at half-maximum. Except for the 2.0-Mev curve the curves all show a definite tendency to decrease at the larger angles and this probably 50 60 70 80 90 K)0 110 120 130 140 150 160 ANGLE IN THE CARBON CENTER OF MASS FIG. 2. The ratio S of the areas under the peaks vs. angle in the carbon center-of-mass system. Dotted line is R(<t>) for 80=125° at 2.5 Mev. See reference 2.means that the P wave is becoming effective. More precise curves are necessary if the P-wave and 5-wave components are to be determined accurately.

Magnetoconductivity of Trigonal Selenium Single Crystals

“…However, in order t o satisfy the continuity condition of the electrical field, the excess of the Hall field in the depletion zones has t o be short circuited by the low resistive regions. The Hall voltage appearing a t the crystal surface is, therefore, too small and likewise the mobility derived from it [18]. Conversely, the magnetoresistance yields too large values for the mobility.…”

Growth and characterization of lead sulfide films deposited on glass substrates

“…In other words, the carrier density is spatially inhomogeneous, and the interpretation of Hall-effect measurements is no longer straightforward. Volger [17] proposed a geometric model for an inhomogeneous material consisting of conducting grains separated by more-resistive inter-granular material. He showed how the measured Hall effect could deviate appreciably from the Hall effect appropriate to the grains in such a configuration.…”

Transport Properties of As-Prepared Al-Doped Zinc Oxide Films Using Sol-Gel Method

“…There are several conduction models in the literature to explain the temperature dependence of conductivity in polycrystalline films. The basic model was proposed by Volger [11] and Petriz [12] and the refinements were done by Orton and Powell [13] and Seto [10]. A polycrystalline film can be thought to be composed of grains with a grain boundary (g.b.)…”