Separating hyperfine from spin-orbit interactions in organic   semiconductors by multi-octave magnetic resonance using coplanar waveguide   microresonators
  Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance, and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators we cover almost five octaves in resonance frequency within a single setup. The measurements with a common pi-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrum with increasing frequency. 
Gajadhar Joshi, Richards Miller, Lillie Ogden, Marzieh Kavand, Shirin   Jamali, Kapildeb Ambal, Suresh Venkatesh, David Schu...
cond-mat.mes-hall cond-mat.mtrl-sci