The change of electrical resistance in a magnetic field (i.e., the magetoresistance) is typically rather small in many materials, but it can have important technological applications when it is sizeable. For instance, the “giant magnetoresistance ” of magnetic multilayer structures provides the basis for magnetic sensors used in hard disks and other devices. However, magnetism is not the only route to a large magnetoresistance. Material inhomogeneities or the sample geometry can also generate a substantial magnetoresistance in non-magnetic systems [1]. It has also been demonstrated that a similar effect can be achieved in a semiconductor subjected to a high electric field, where the electrical transport is no longer ohmic [2]. The aim of this project is to determine whether the inhomogeneous electric field present in this non-linear transport regime is sufficient to produce a large magnetoresistance or whether something further is required.
References
[1] M. M. Parish, P. B. Littlewood, Non-saturating magnetoresistance in heavily disordered semiconductors, Nature volume 426, number 6963, 2003 [2] M. P. Delmo et. al., Large positive magnetoresistive effect in silicon induced by the space-charge effect, Nature volume 457, number 7233, 2009Supervisor: A/Prof. Meera Parish
See https://www.monash.edu/science/schools/physics/honours/honours-project to apply.