Ti_(1-x)Co_xO_(2-δ)/AlO_x/Fe_(0.1)Co_(0.9) magnetic tunnel junctions with varied AlO_x thickness

摘要

Magnetic tunnel junctions are fabricated by laser molecular-beam epitaxy employing a room temperature ferromagnetic semiconductor Ti_(1-x)Co_xO_(2-δ) and a ferromagnetic metal Fe_(0.1)Co_(0.9) as electrodes and an AlO_x tunnel barrier. The thickness of the AlO_x barrier is systematically varied on a substrate during the growth by stencil mask. The junction resistance increases with the barrier thickness exponentially. The differential conductance and the tunneling magnetoresistance are significantly asymmetric with respect to bias voltage at low temperature, possibly due to the asymmetric junction structure and/or the degraded interface of AlO_x/Fe_(0.1)Co_(0.9).