THIN MAGNETIC FILM HAVING HIGH PERMEABILITY AND EXCELLENT FREQUENCY CHARACTERISTICS

PURPOSE:To provide a thin ferromagnetic film with a high permeability without applying thermal treatment after formation of the film and to maintain this magnetic characteristic up to a high frequency area by splitting the film into strips at the angle in specified range from an easy magnetization direction of the film. CONSTITUTION:A ferromagnetic thin film is splitted into strips at an angle within 10 to 70 degrees from an easy magnetization direction of the film. The splitting direction is at the angle of theta with the easy magnetization direction. If theta ranges from 10 to 70 degrees, a permeability increases in a high frequency area. It is preferable to make the angle range from 20 to 50 degrees. If theta is less than 10 degrees or larger than 70 degrees, a frequency characteristic of permeability is almost same at that of the conventional thin magnetic film and there is very small improvement in characteristics. If the stripped thin magnetic film is split in the mm order, there is some improvement in characteristics. When the splitting width is larger than 5mm, however, the improvement in characteristics gets smaller and smaller. Then, the maximum splitting width is 5mm. As the strip width gets narrower, a resonance frequency increases. With the strip width smaller than 5mum, a sudden drop in permeability is caused. Then, the lower limit is 5mum.