A magnetic organic-inorganic composite: Synthesis and characterization of magnetic 5-aminosalicylic acid intercalated layered double hydroxides

A core-shell structured magnetic layered organic inorganic material involving 5-ammosalicylic acid (5-ASA) intercalated Zn-Al layered double hydroxides (LDHs) and magnesium ferrite (MgFe2O4) is assembled by a coprecipitation method. The powder X-ray diffraction results show the coexistence of the clear but weak diffractions of MgFe2O4 and ordered relatively stronger reflections of 5-ASA intercalated LDHs. The TEM image of magnetic 5-ASA intercalated LDHs reveals that the LDHs layer covers the MgFe2O4 particles or their aggregates with particle size of 50-80 nm. The vibration sample magnetization (VSM) measurements exhibit the increase in saturation magnetization of magnetic 5-ASA intercalated LDHs samples with increasing amount of magnetic core. The XPS analyses account for a majority of Zn, Al and O atoms on the surface of magnetic particles. It is suggested that the magnetic core MgFe2O4 was coated with LDHs layer probably through Zn-O-Mg and Al-O-Mg linkages, and a core-shell structured model is tentatively proposed. (c) 2005 Elsevier Inc. All rights reserved.