Low-field colossal magnetoresistance in manganite tunnel spin valves

摘要: We report on the magnetoresistive properties of all-oxide tunnel spin valves in which electrodes mixed valence manganites (La0.7Sr0.3MnO3) are separated by a thin insulating layer. The structures were prepared Pulsed Laser Deposition and several barriers used including PrBa2(CuGa)3O7, CeO2 SrTiO3. latter gives largest effect where trilayer's resistance is increased factor 5.5 at 50 Gauss 4.2 K. Analysis temperature variation barrier resistivity shows that dramatic loss above 150 K due to reduced oxygen content interface between La0.7Sr0.3MnO3 Solving this problem should lead similar results room temperature.