A high-performance permeance meter and its application to measuring the complex permeability of thin Fe-Si-Al-N films for perpendicular magnetic recording heads

Abstract
A high-performance permeance meter has been developed to measure the permeability of thin films for perpendicular magnetic recording heads. The instrument is able to determine small permeance (about 20 μm) with a good signal-to-noise ratio in the frequency range of 0.5–120 MHz and, moreover, to reduce the conventional error in the high-frequency region. The complex permeability of an Fe-Si-Al-N film 200 nm thick for perpendicular magnetic recording heads was measured, and the real part of the permeability was about 3500 with a −1-dB frequency of about 80 MHz.