Hall Voltage and Magnetoresistance of Bi Measured by a Sum Frequency Method in a Belt Apparatus

Abstract

An alternating magnetic field, 1.4 kG in amplitude at 5 Hz, was obtained in a belt type of high pressure apparatus by the use of conical pistons made of hardened high speed tool steel, permitting operation up to 50 kilobar. A frequency of 12 Hz was used for the current through the sample, and the Hall voltage was synchronously detected at 17 Hz. A signal yielding the coefficient of magnetoresistance was extracted at 22 Hz, using another lock‐in amplifier. The Ohmic resistance may also be measured in the same experiment, and, by making certain assumptions, the variation of the carrier density and the hole and electron mobilities of a semimetal may be determined. Data for polycrystalline Bi at room temperature are given.