Theory of tunneling magnetoresistance for epitaxial systems

The tunneling current for electrons tunneling between crystalline ferromagnetic electrodes through an epitaxial crystalline barrier can be calculated from first principles. These calculations show that the wave function symmetry can be exploited to achieve very high tunneling magnetoresistance. For the Fe(100)vertical bar MgO(100) vertical bar Fe(100) system, the calculated conductance is much higher and its decrease with MgO thickness is much slower than has been estimated using a simple free electron-barrier model.