Including fringe fields from a nearby ferromagnet in a percolation theory of organic magnetoresistance

Abstract

Random hyperfine fields are essential to mechanisms of low-field magnetoresistance in organic semiconductors. Recent experiments have shown that another type of random field --- fringe fields due to a nearby ferromagnet --- can also dramatically affect the magnetoresistance. A theoretical analysis of the effect of these fringe fields is challenging, as the fringe field magnitudes and their correlation lengths are orders of magnitude larger than that of the hyperfine couplings. We extend a recent theory of organic magnetoresistance to calculate the magnetoresistance with both hyperfine and fringe fields present. This theory describes several key features of the experimental fringe-field magnetoresistance, including the applied fields where the magnetoresistance reaches extrema, the applied field range of large magnetoresistance effects from the fringe fields, and the sign of the effect.

arXiv comment5 pages, 4 figures. Accepted by Phys. Rev. B Rapid Communications

References in corpus (5)

• Large magnetoresistance at room-temperature in semiconducting polymer sandwich devices
• Large magnetoresistance at room-temperature in small molecular weight organic semiconductor sandwich devices
• Spin-flip induced magnetoresistance in positionally disordered organic solids
• Tunneling anisotropic magnetoresistance in organic spin valves
• The effects of spin-spin interactions on magnetoresistance in disordered organic semiconductors

Cited by in corpus (4)

• Organic Magnetoelectroluminescence for Room Temperature Transduction between Magnetic and Optical Information
• Organic magnetoresistance under resonant ac drive
• Manipulation of the electroluminescence of organic light-emitting diodes via fringe fields from patterned magnetic domains
• Spin dynamics and spin-dependent recombination of a polaron pair under a strong ac drive