Macroscopic system for studies of magnetic dipolar interaction in small particles

A magnetic macroscopic system with free compass needles has been assembled to study dipolar interactions in small particles. Hysteresis loops and the magnetization processes as a function of the system size and dimensions are studied. By changing the number of needles and their disposition, we can vary the magnetostatic coupling and change the magnetic properties of the system. These studies can help to understand better of the role of the magnetostatic coupling in small particle systems.