A bias voltage dependent positive magnetoresistance in Cox–C1−x/Si heterostructure

Abstract

Co x – C 1 − x granular films were deposited on n-type Si substrates by pulsed laser deposition method. The heterostructure, investigated in current-perpendicular-to-plane geometry, has a bias voltage dependent positive magnetoresistance (MR), and at room temperature, the MR value reaches 16% at magnetic field H=2.5 kOe and bias voltage of 6 V. All MRs have saturated behavior when H>2.5 kOe. The mechanism of this MR is attributed to that the applied magnetic field and local random magnetic field modulate the ratio of singlet and triplet spin states leading to the MR.