Magnetoresistance characteristics of heterostructures grown on Si(111) by molecular beam epitaxy

magnetic tunnel junctions (MTJs) have been investigated to demonstrate the tunnel magnetoresistance effects. We fabricated (20 nm)/(2 nm)/(15 nm) heterostructures epitaxially on a Si(111) substrate by molecular beam epitaxy. The current-voltage characteristics for the MTJs measured at room temperature (RT) were well fitted to Simmons’ equation. The fitting yields the barrier height φ=2.5 eV and the barrier thickness d=1.26 nm. The magnetoresistance ratio for the MTJs were approximately 0.28% under a bias voltage of 20 mV at RT.