Development of MFM with Magnetic Fields Applied by Orthogonal Electromagnets and its Applications to Analysis of Magnetic Domain Structures

We developed a magnetic force microscope (MFM) where magnetic fields were applied by orthogonal electromagnets. This equipment can be used to observe magnetic domains by specifying an arbitrary angle while applying an external magnetic field of 5 kOe or less. A dot and a rectangular thin film made of permalloy were measured with this equipment. The chirality of the vortex state in the permalloy dot could be determined by using this apparatus. Furthermore, the shape of the closure domain changed every time the direction of the magnetic field was changed by 45 degrees. These results are discussed in detail together with the micromagnetics simulations.