An Active Head Using the Magnetoresistive Effect in the High Frequency Region

Abstract

A highly sensitive magnetic read-out head HFMRH High Frequency Magnetoresistive Head ) is introduced, which is based on a new magnetoresistlve (HR) effect.-The author has experimentally discovered that a conventional HR head shows the new HR effect at a frequency (fr) so high as to cause ferromagnetic resonance (FMR). Head performance was evaluated with a new parameter, modified HR ratio (ARmax/JR ARmax maximum resistance change, R:resistance) which is proportional to the signal-to-noise ratio (SNR). The experimental results showed that the modified HR ratio at fr can be much larger than that at a frequency lower than fr. It has been confirmed that the new effect can be applied to a magnetic read-out head with a higher output level and a higher SNR than the normal HR effect observed with direct current (dc). The new head design is promising for realizing future ultra high-density magnetic recording systems.