J. Phys. D: Appl. Phys. 40, 3271 (2007)
Y F Chen and M Ziese
Tunnelling junctions with a SrTiO3 barrier, one La0.7Sr0.3MnO3 electrode and one Fe3O4 electrode were fabricated by pulsed laser deposition. The magnetization, current–voltage characteristics and magnetoresistance of the junctions were measured. The junction magnetoresistance was always negative, strongly bias-dependent at low temperatures and vanished with increasing temperature above about 135 K. Its field dependence was not correlated with the field dependence of the magnetization. This junction magnetoresistance is attributed to indirect tunnelling—as evidenced by current–voltage characteristics—between the Fe3O4 and the La0.7Sr0.3MnO3 electrodes.