Anomalous organic magnetoresistance from competing carrier-spin-dependent interactions with localized electronic and nuclear spins

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Wang Y., Harmon N. J., Sahin-Tiras K., Wohlgenannt M., Flatte M. E.

PHYSICAL REVIEW B, vol.90, no.6, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 90 Issue: 6
  • Publication Date: 2014
  • Doi Number: 10.1103/physrevb.90.060204
  • Journal Name: PHYSICAL REVIEW B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Erciyes University Affiliated: No

Abstract

We describe a regime for low-field magnetoresistance in organic semiconductors, in which the spin-relaxing effects of localized nuclear spins and electronic spins interfere. The regime is studied by the controlled addition of localized electronic spins to a material that exhibits substantial room-temperature magnetoresistance (similar to 20%). Although initially the magnetoresistance is suppressed by the doping, at intermediate doping there is a regime where the magnetoresistance is insensitive to the doping level. For much greater doping concentrations the magnetoresistance is fully suppressed. The behavior is described within a theoretical model describing the effect of carrier spin dynamics on the current.