Mesoporous lanthanum–manganese oxides with nanoscale periodicity, high surface area and ferromagnetic property

Designing and synthesis of inorganic materials containing magnetic elements with nanoscale periodicity is one of the areas of major research interests due to their potential memory applications. A series of ordered mesoporous lanthanum–manganese oxides has been synthesized hydrothermally using saturated fatty acids as templates in the presence of ethylenediamine (EDA) as mineralizer. Templates are removed from these as-synthesized materials through repeated ethanol–EDA extraction at 333 K. As-synthesized and template-free samples have been characterized by powder X-ray diffraction, transmission and scanning electron microscopy, N2 sorption and X-ray photoelectron spectroscopic studies. The observed BET surface area for the template-extracted sample synthesized by using lauric acid is 304 m2 g−1, which on further heating at 673 K resulted in a nonstoichiometric porous LaMnO3+δ manganite material having a further improved BET surface area of 406 m2 g−1. The low temperature magnetic measurements revealed that the material becomes ferromagnetic at 45 K.

Ordered mesoporous lanthanum manganese oxides have been synthesized hydrothermally using long chain fatty acids as templates. Template-free materials showed good surface area and high concentration of MnIV. Magnetic measurement suggests ferromagnetic behavior of the material having TC of ca. 45 K.Figure optionsDownload as PowerPoint slideHighlights
► New mesoporous lanthanum–manganese oxide framework.
► Nanoscale periodicity of materials containing magnetic element.
► Mesoporosity and high surface area material.
► Ferromagnetic property.