Recording of single-particle hysteresis loops with differential phase contrast microscopy

The magnetic behaviour of laterally patterned structures on a micrometer or nanometer scale in external magnetic fields can be described by their hysteresis loops. However, it is very difficult to record the hysteresis loop of a single (sub-) micron-sized particle. Furthermore, extensive calculations are necessary in order to interpret the shape of the loop and to conclude the micromagnetic domain configuration in the sample from the hysteresis loop only. We have developed a technique which yields both the hysteresis loop and the magnetic domain structure simultaneously. This method uses differential phase contrast microscopy and a microscope with remote control capability for the automatic recording of a single-particle hysteresis loop.