Epitaxial Cr-doped Ti2O3 films show giant negative magnetoresistance up to −365% at 2 K. The resistivity of the doped samples follows the behavior expected of spin smagneticd polarons at low temperature. Namely, r =r0 expsT0 /Tdp, where p=0.5 in zero field. A large applied field quenches the spin polarons and p is reduced to 0.25 expected for lattice polarons. The formation of spin polarons is an indication of strong exchange coupling between the magnetic ions and holes in the system. © 2005 American Institute of Physics.
Wang, Zhenjun; Hong, Yuanjia; Tang, Jinke; Radu, Cosmin; Chen, Yuxi; Spinu, Leonard; Zhou, Weilie; and Tung, Le Duc (2005). "Giant negative magnetoresistance of spin polarons in magnetic semiconductors–chromium-doped Ti 2 O 3 thin films." APPLIED PHYSICS LETTERS .86, 082509-1-082509-3.