Large positive magnetoresistance in germanium

A large positive magnetoresistance (MR) effect is observed in In/Ge/In structures. The current–voltage characteristics of the structure show a nonlinear behavior (even breakdown at higher voltages), caused by the space-charge effect. It is found that large magnetic field and low temperature can suppress the breakdown, resulting in a large value of MR. The MR is measured to be 1300% with the external magnetic field of 2 T and applied voltage of only 8.5 V at room temperature. This work may be beneficial to the germanium based magnetic sensing industry.