Electrical and magnetoelectronic properties of La0.7Sr0.3MnO3/SiO2/p-Si heterostructure for spintronics application

An experimental study of p-silicon (Si)/La0.7Sr0.3MnO3 (LSMO) junction in which the LSMO and silicon are separated by a thin interfacial silicon dioxide (SiO2) layer has been fabricated. Two type of SiO2 layer has been discussed here – one is native oxide and another one is thermal oxide. The thermal SiO2 film is grown on Si by annealing it at 800 °C in oxygen atmosphere. The LSMO film of about 64 nm thick has been grown on SiO2 at 800 °C substrate temperature in 10−1 mbar oxygen pressure by Pulsed Laser Deposition technique. The LSMO/SiO2/Si heterostructure exhibits MOS diode-like behavior with all type of possible current flow mechanisms (such as thermionic emission, tunneling, recombination degeneration, etc.) through the heterojunction. The high field Fowler-Nordheim [ln(JFN/E2) vs 1/E] plot at different temperatures confirms that the dominating transport mechanism across the heterostructure is tunneling. The junction resistance changes under magnetic field and the junction magnetoresistance is found to be ∼31% with 1T applied magnetic field at room temperature at a bias voltage of 2.2 V. The capacitor-voltage characteristics confirm the presence of trap charges.