X-Ray Diffraction study of Langmuir-Blodgett Films of Mn-Arachidate

To elucidate the structure of organic thin films having magnetic properties, we performed X-ray diffraction, differential scanning calorimetry and electron paramagnetic resonance measurements on the Langmuir-Blodgett (LB) films of Mn-arachidate. The LB films of Mn-arachidate were found the most feasible system for the study of magnetic thin films due to their reproducibility. We found that orientation of the fatty acid molecules correlates with the number of layers or thickness of films; films having less than three layers show the perpendicular orientation of fatty acid molecules to the substrate surface. However, films of more than five layers exhibit the tilt orientation with respect to the layer normal. The tilt angle increases with the thickness of the LB films. Homogeneous distributions of the crystalline size were found in the LB films.