Structure and properties of (1-x)La0.67Sr0.33MnO3/xMnOδ multicomponent composite

(1-x)La0.67Sr0.33MnO3/xMnOδ [(1-x)LSMO/xMnOδ] multicomponent composites were prepared. Their structure and properties were investigated as function of composition. X-ray diffraction and x-ray photoelectron spectroscopy confirmed the coexistence of MnO, Mn2O3 and MnO2. It was found that MnOδ introduction led to decreased average grain size and metal-insulator transition temperature. But it can increase maximum resistivity and magnetoresistance. The corresponding values were 2.0 μm, 370 K, 0.017 Ω cm, −24.7% (10 K, 2 T) for x = 0 and 0.7 μm, 225 K, 1.899 Ω cm and −25.6% (10 K, 2 T) for x = 0.3. However, the ferromagnetic Curie temperature was almost composition-independent with the value of 305 K. These results indicate that forming multicomponent composite by introducing ferromagnetic second phases can suppress the drawbacks of conventional ferromagnetic materials.