Giant negative magnetoresistance of spin polarons in magnetic semiconductors–chromium-doped Ti2O3 thin films

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Wang, Zhenjun ; Hong, Yuanjia ; Tang, Jinke ; Radu, Cosmin ; Chen, Y. (Yuxi) ; Spinu, Leonard ; Zhou, Weilie ; Tung, Le Duc (2005)
  • Publisher: American Institute of Physics
  • Related identifiers: doi: 10.1063/1.1874302
  • Subject: QC | TK
    arxiv: Condensed Matter::Strongly Correlated Electrons | Condensed Matter::Materials Science

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 (magnetic) polarons at low temperature. Namely, rho= rho0 exp(T0/T)p, 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.
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