  A magnetic tunnel junctions composed of room temperature ferromagnetic
semiconductor rutile Ti1-xCoxO2-d and ferromagnetic metal Fe0.1Co0.9 separated
by AlOx barrier showed positive tunneling magnetoresistance (TMR) with a ratio
of ~11 % at 15 K, indicating that Ti1-xCoxO2-d can be used as a spin injection
electrode. The TMR decreased with increasing temperature and vanished above 180
K. TMR action at high temperature is likely prohibited by the inelastic
tunneling conduction due to the low quality of the amorphous barrier layer
and/or the junction interface.
