Voltage and Temperature Dependence of High-Field Magnetoresistance in Arrays of Magnetic Nanoparticles - Condensed Matter > Materials ScienceReport as inadecuate




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Abstract: Huge values of high field magnetoresistance have been recently reported inlarge arrays of CoFe nanoparticles embedded in an organic insulating lattice inthe Coulomb blockade regime. An unusual exponential decrease ofmagnetoresistance with increasing voltage was observed, as well as acharacteristic scaling of the magnetoresistance amplitude versus thefield-temperature ratio. We propose a model which takes into account theinfluence of paramagnetic impurities on the transport properties of the systemto describe these features. It is assumed that the non-colinearity between thecore spins inside the nanoparticles and the paramagnetic impurities can bemodelled by an effective tunnel barrier, the height of which depends on therelative angle between the magnetization of both kind of spins. The influenceon the magnetotransport properties of the height and the thickness of theeffective tunnel barrier of the magnetic moment of the impurity, as well as thebias voltage are studied. This model allows us to reproduce the largemagnetoresistance magnitude observed and its strong voltage dependence, withrealistic parameters.



Author: Reasmey P. Tan, Julian Carrey, Marc Respaud

Source: https://arxiv.org/



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