Creating and understanding magnetotransport properties in manganite based devices

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An important class of devices, including those used in magnetic sensing and recording applications, function because their resistances change significantly with the strength and direction of the magnetic field. My proposed research is aimed at understanding and manipulating these properties in a unique set of metamaterials based on manganese oxide (manganite) thin films. In these systems, we plan to control the shape, size and proximity of the small magnetic inhomogeneities that naturally exist within them. Such manipulation will enable us to produce record breaking values and/or never-seen-before electrical properties that are important for techonology. Methods for producing such novel behaviour include adjusting the strain acting on the device and using electron beams to write nanometer scale patterns into the magnetic inhomogeneities. The electrical properties include the anisotropic magnetoresistance (AMR), i.e. the change in the resistance that depends on the orientation of the magnetic field, and the tunneling magnetoresistance (TMR), a phenomenon that is commonly associated with a quantum mechanical property where electrons can apparently slip through a “barrier” which would normally impede its motion. Hence, the general goals of our investigations are twofold: (i) improve the understanding of the interesting scientific issues behind these interesting devices, and (ii) enable researchers to potentially utilize their highly sensitive tunability for new applications.