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Pseudo Spin Valve Behavior in Colloidally Prepared Nanoparticle Films

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journal contribution
posted on 24.06.2019, 00:00 by Benjamin H. Zhou, Jeffrey D. Rinehart
Magnetoresistance provides a high-precision, versatile sensing mechanism that has continuously advanced in tandem with methods for top-down engineering of high-precision multilayer devices. Materials composed of solution-prepared nanocrystals can replicate some of the behavior of traditional magnetoresistive stacks but are limited by their intrinsic response mechanism: a gradual shift from low to high resistance with field. To fundamentally alter this behavior, we demonstrate the first instance of any form of spin valve behavior arising from a nanoparticle composite magnetoresistor. Single-layer films of varying CoFe2O4 to Fe3O4 nanoparticle ratios are used to show how the low-field sensitivity can be tuned to values exceeding those of either single-component material. Additionally, the sensitivity is shown to be a simple function of the magnetization of the individual component materials.