Structure of Strip-like Magnetic Core of Thin Film Inductor

In this paper, a new type of strip-like magnetic core is proposed. The core is prepared by separating the nearest-neighbor strip, which is made of SiO2, by a gap (d), and then sputtering a magnetic film under an external field applied perpendicular to the exciting direction. The width of the strip lines (Ws) varied from 10 to 1000 ¿m. The arrangement of these high-density strip lines is confirmed by the domain structure and the frequency dependence of the permeability. When the gap is greater than the thickness of the magnetic film, the magnetic domains are independent of each other, and the initial permeability is the same as that of the strip line film which is separated by space. When the strip width is decreased, the domain width decreases and the number of domains increases. The strip-like magnetic core was used in a thin film inductor. The inductance at 20 MHz and the maximum value of the quality factor (Qmax) in the experimental inductor show maxima near Ws=300 to 500 ¿m. Such magnetic cores are useful for increasing the inductance and quality factor of thin-film inductors.