Colossal magnetoresistance of the inhomogeneous ferromagnetic semiconductor HgCr2Se4

A new method is described for attaining high magnetoresistance in inhomogeneous magnetic materials, which makes use of the formation of a depleted layer and a contact potential difference at the interface separating two semiconductors with different Fermi levels and the magnetic-field-induced variation in the contact potential difference and thickness of the interface layer. The proposed model of the magnetoresistive structure is realized on the basis of the HgCr2Se4 magnetic semiconductor. Layers of n-HgCr2Se4 up to a few tens of microns thick were prepared on the surface of p-HgCr2Se4 bulk single crystals by the diffusion technique. Application of a magnetic field stimulated in the structures a strong (by a factor of more than 200) increase of the current flowing through the n-layer.