We have grown heterostructures associating half-metallic La2∕3Sr1∕3MnO3 (LSMO) bottom electrodes and ferromagnetic La0.1Bi0.9MnO3 (LBMO) tunnel barriers. The layers in the heterostructures have good structural properties and top LBMO films (4 nm thick) have a very low roughness when deposited onto LSMO∕SrTiO3(1.6nm) templates. The LBMO films show an insulating behavior and a ferromagnetic character that are both preserved down to very low thicknesses. They are thus suitable for being used as tunnel barriers. Spin-dependent transport measurements performed on tunnel junctions defined from LSMO∕SrTiO3∕LBMO∕Au samples show a magnetoresistance of up to ∼90% at low temperature and bias. This evidences a spin-filtering effect by the LBMO layer, with a spin-filtering efficiency of ∼35%.