Magnetostatic interaction in multi-shell Ni80Fe20/Cu composite wires

Magnetostatic interaction in multilayered structure materials has long been a key to optimize the magnetic devices due to the modulation of their magnetic properties. In this study, the multi-shell Ni80Fe20(tout)/Ni80Fe20(tin)/Cu composite wires were prepared by magnetron sputtering. The results show that the hysteresis loops of the multi-shell composite wires do not present significant changes compared with the single shell composite wire. A four-peak structure GMI profile may appear when both the inner and outer Ni80Fe20 shell have a preferred circular anisotropy, which indicated that the strong dipole interactions existed between the shells. In such multi-shell system, the response of dipole field Hdi to the driving frequency is against the compensation field Hcomp. If the inner shell has axial anisotropy structure, there are almost no dipole interaction observed according to disappearance of the interaction energy. All the results suggest a facile way to achieve a higher GMI response, and a sensitive method, especially in the low magnetic field region, to investigate the magnetic interactions in complicated composite structure materials.