Magnetic nanoparticles are of significant importance due to their potential applications in the fields of science, engineering and nanomedicine. Using the Langmuir-Blodgett technique, 2D assemblies of Fe3O4 nanoparticles can be deposited on solid substrates at various surface pressures. Formation of magnetic nanodomains in LB films and their successful transformation to glass substrates provides fundamental insights into the formation of magnetic films under both dipole-dipole interactions and mechanical compression, which is very important for experimental and applied research. Furthermore, vast LB films of closely packed nanoparticles were prepared which are very important in data storage devices. This technique enables the application of an external magnetic field parallel to the substrates. The presence of the external magnetic field at high surface pressure close to collapse point improves the quality of LB films of closely packed nanoparticles. The effect of an external magnetic field at smaller surface pressures converts nanodomains and chains into striped structures. Ordered magnetic nanoparticles has an essential role in many areas of science and engineering. As a fast and affordable method, this technique helps achieve a high degree of ordering.
