Observation of minority spin character of the new electron doped manganite La0.7Ce0.3MnO3 from tunneling magnetoresistance

We report the magnetotransport characteristics of a trilayer ferromagnetic tunnel junction built of an electron doped manganite (La0.7Ce0.3MnO3) and a hole doped manganite (La0.7Ca0.3MnO3). At low temperatures the junction exhibits a large positive tunneling magnetoresistance (TMR), irrespective of the bias voltage. At intermediate temperatures below T(C) the sign of the TMR is dependent on the bias voltage across the junction. The magnetoresistive characteristics of the junction strongly suggest that La0.7Ce0.3MnO3 is a minority spin carrier ferromagnet with a high degree of spin polarization, i.e., a transport half-metal.