Deep eutectic solvents (DESs), a kind of ionic liquids, are expected as a novel solvent for electroplating due to their unique properties such as low vapor pressure, non-combustibility, high thermal stability, and high conductivity. We have employed DES as a solvent to obtain soft magnetic Fe-Ni films and have reported that glycine is an effective bath additive to reduce the coercivity in Fe-rich Fe-Ni films. In the present study, we employed boric acid as an additive in the plating bath and investigated the effect of boric acid on the magnetic and structural properties of Fe-Ni films. The addition of the boric acid reduced the coercivity of the Fe-Ni films. In particular, the boric acid dramatically reduced the coercivity in Fe-poor films, and this behavior was quite different from that for the glycine. From the result of the TEM observation, we confirmed that the Fe-Ni films with low coercivity had a fine crystal structure, which suggested that the fine structure supported improving the soft magnetic properties.

The multi-domain particle model for the magnetization analysis of electrical steel sheets requires long computation time when the applied magnetic field is large. In this study, we propose a method that can efficiently minimize the internal energy in two steps: the energy minimization by domain wall motion and the energy minimization including magnetization rotation. The proposed method can significantly reduce the computation time while maintaining the accuracy of magnetization analysis.

High frequency magnetic measurements for low permeability toroidal cores are demonstrated using various primary and secondary coils on low permeability magnetic toroidal cores, and effects of coils on their precision is discussed. As the number of turns in primary and secondary coils are reduced, measured permeability shows higher dispersion. This fact relates to the deviation of the strength of magnetizing field due to the small number of primary windings. It is also demonstrated several winding methods of primary coil to reduce the dispersion.

In this paper, a streamline display method for magnetic flux density and magnetic field strength vectors in a three-phase induction motor model core is presented, and the relationship between streamlines and magnetic properties is investigated. It is possible to visualize the vector magnetic properties distribution by representing the magnetic flux density and the magnetic field strength vector with the streamlines. In addition, the time variation of the streamlines of the magnetic flux density and magnetic field strength vectors, and magnetic energy was compared. It was clear that the magnetic energy did not necessarily increase in the areas where the magnetic flux density and magnetic field strength increased because these vectors have the spatial phase difference.

Vector magnetic properties of permendurs have been investigated by using a vector magnetic property measurement apparatus to select a magnetic material suitable as a motor core material. When a motor is rotated at high speed by high-frequency excitation to increase power of a motor, a magnetic material with a high saturation magnetic flux density and a low iron loss is useful for a motor core. However, iron loss versus frequency characteristics under rotating magnetic flux density conditions of permendurs have not been sufficiently investigated. Moreover, the magnetic characteristics of permendurs made by different manufacturers have not been compared. Therefore, in this paper, the vector magnetic properties under rotating magnetic flux density conditions of two kinds of permendur made by different manufacturers are measured and compared for iron losses.