Room temperature giant positive junction magnetoresistance of NiFe2O4/n-Si heterojunction for spintronics application

Electronic- and magnetic-transport properties of NiFe2O4 (NFO)-SiO2-Si heterojunction fabricated by depositing NFO thin films on silicon substrates with the intermediate native oxide (SiO2) layer have been investigated in details. The current-voltage (I-V) characteristics across the junction have been recorded in the temperature range of 10-300 K. All I-V curves show non-linear behavior throughout the temperature range. The dominating current transport mechanism is found to be temperature dependent tunneling assisted by Frenkel-Poole type emission. In this paper, we report the junction magnetoresistance (JMR) properties of this heterojunction in the temperature range of 10-300 K. With increasing temperature, the JMR of the heterojunction increases accordingly. The high positive JMR (~54%) has been observed at room temperature (RT). The origin of high positive JMR at RT is attributed to efficient spin-polarized carrier transport across the junction.