Driving conditions dependence of magneto-electroluminescence in   tri-(8-hydroxyquinoline)-aluminum based organic light emitting diodes
  we investigated the magneto-electroluminescence (MEL) in tri-(8-hydroxyquinoline)-aluminum based organic light-emitting diodes (OLEDs) through the steady-state and transient method simultaneously. The MELs show the great different behaviors when we turn the driving condition from a constant voltage to a pulse voltage. For devices driven by the constant voltage, the MELs are similar with the literature data; for devices driven by the pulse voltage, the MELs are quite different, they firstly increase to a maximum then decrease as the magnetic field increases continuously. Negative MELs can be seen when both the magnetic field and driving voltage are high enough. 
Qiming Peng, Jixiang Sun, Xianjie Li, Mingliang Li, and Feng Li
physics.chem-ph cond-mat.mtrl-sci