We report a procedure to fabricate a tri-layer La 0 . 6 7 Sr 0 . 3 3 MnO 3 /La 0 . 8 5 Sr 0 . 1 5 MnO 3 /La 0 . 6 7 Sr 0 . 3 3 MnO 3 tunneling magnetoresistance (TMR) device deposited on an SrTiO 3 substrate. The devices have been characterized by high-resolution transmission electron microscopy (TEM), tunneling current versus voltage, and magnetoresistance (MR). The TMR phenomenon has been observed up to 320K. A procedure to further optimize this device has been proposed.