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

Abstract

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 10–300K. 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 10–300K. 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.