Improved tunneling magnetoresistance at low temperature in manganite   junctions grown by molecular beam epitaxy
  We report resistance versus magnetic field measurements for a La0.65Sr0.35MnO3/SrTiO3/La0.65Sr0.35MnO3 tunnel junction grown by molecular-beam epitaxy, that show a large field window of extremely high tunneling magnetoresistance (TMR) at low temperature. Scanning the in-plane applied field orientation through 360^/circ, the TMR shows 4-fold symmetry, i.e. biaxial anisotropy, aligned with the crystalline axes but not the junction geometrical long axis. The TMR reaches ~ 1900% at 4K, corresponding to an interfacial spin polarization of > 95% assuming identical interfaces. These results show that uniaxial anisotropy is not necessary for large TMR, and lay the groundwork for future improvements in TMR in manganite junctions. 
Robert Werner, Alexandr Yu. Petrov, Lucero Alvarez Mino, Reinhold   Kleiner, Dieter Koelle and Bruce A. Davidson
cond-mat.mes-hall cond-mat.mtrl-sci