Huge magnetoresistive effects using space charge limited current in ZnO/SiO_2 system

摘要

Huge magnetoresistive effects were observed in a metal/insulator current-in-plane (CIP) diode feeding space charge limited (SCL) current. The insulator laterally toward opposite gold (Au) electrodes was fabricated on a SiO_2 substrate by the standard photolithography method using dry etching. The insulator consisted of a SiO_2/ZnO/SiO_2/ZnO multilayer sputtered on the substrate. Current-voltage curves showed Ohmic property and SCL current characteristics accompanied by Child-Langmuir and Mott-Gurney laws derived from first order differential calculus. Current-magnetic field curves indicated the huge magnetoresistive effects up to 10~(10)% under the magnetic field of 0.3 T at room temperature. The current-magnetic field curves have even symmetry for the applied magnetic field. The Au/insulator CIP diode is abruptly switched between a conducting state and an insulating state by the applied magnetic field.