A Negative-Resistance Magnetoresistive Circuit

摘要

A negative-resistance circuit that consists of a magnetoresistor situated in the magnetic field produced by two magnetomotive forces (MMF's) is described. The winding of one of the MMF's is connected serially with the magnetoresistor. The negative-resistance region is determined by the condition b-B > dB/d lnRm, where B is the magnetic field at the magnetoresistor, b is the bias field (produced by the second MMF alone), and Rm(B) is the magnetic-field dependence of the magnetoresistor. For a quadratic magnetoresistor characteristic, this condition becomes Rm(b) > 4R(0). The negative-resistance characteristics of a superconductor magnetoresistor are presented. Switching of the modes and the stable amplification region of the circuit is discussed. Experimental results for indium antimonide (at 193K) and bismuth (at 4.2K) magnetoresistors are given. (Author)