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Description
The experimental evidence of large magnetoresistance in magnetite pellets is provided in this paper. Applying magnetic field along the length of the four-point probe resistivity monitoring, on the surface of a bulk magnetite pellet, results in elevated magnetoresistance change in the order of 100$\%$. Measurements were realized in $10^{-3}$ mbar vacuum with excitation currents from 0.1 A up to 0.5 A, with magnetic field from 0 mT up to 250 mT. After the transient decrease of resistance due to the increase of the carrier number because of the semiconducting nature of the magnetite pellets, the final resistance of the sample was dependent on the externally applied field. A typical response is illustrated in Figure 1. The reason for such drop of resistivity is the parallelization of the magnetic flux $B$ of the magnetite pellet with the excitation current, thus resulting in the reduction of the Lorentz force on the conducting carriers, reducing the Lorentz scattering effect.
Fig. 1 Steady state resistance dependence of magnetite pellets on magnetic field, for different electric currents transmitted through the pellet.
