Epitaxial SrTiO(3) tunnel barriers on Pt/MgO substrates

Abstract

Tunnel junction devices employing epitaxial, (001)-oriented SrTiO(3) barriers with thicknesses between 4 and 5nm were fabricated by sputtering on (001) Pt/MgO substrates. The quality of the Pt/SrTiO(3) interface was characterized by transmission electron microscopy and the current transport studied as a function of temperature and bias field. At low voltages the junctions showed excellent insulting properties and temperature dependent, non-linear current-voltage characteristics. If junctions were biased to high fields (>1.25 MV/cm) current hysteresis was observed. The hysteresis is shown to be due to time-dependent tunnel barrier properties at high fields. (C) 2008 The Japan Society of Applied Physics.