Hole-Doped Manganites Based Tunneling Junctions With Isostructural Barrier Layer

La(0.7)Sr(0.3)MnO(3)/La(0.96)Sr(0.04)MnO(3)/La(0.7)Sr(0.3)MnO(3) magnetic tunnel junction device have been fabricated on SrTiO(3) (STO) substrate. A large tunneling magnetoresistance (TMR) of 134% was observed from the junction with an antiferromagnetic insulating barrier layer (2 nm) at a temperature 4.2 K. Current-voltage (l-V) characteristic of the junction is consistent with a tunneling process at low temperature. A simulation based on Simmons' tunneling model give a barrier-layer thickness d approximate to 5 nm and an average barrier potential height Phi approximate to 0.1 eV, respectively. The results indicate that the large TMR is related to crystallographic similarity between La(0.7)Sr(0.3)MnO(3) and La(0.96)Sr(0.04)MnO(3) compounds, which should minimize lattice mismatch between the electrodes and the barrier layers.