Amorphous Fiber Core Head with Low Power Dissipation for Magnetic Field Modulation on Magneto-Optic Recording

CoFeSiB system soft magnetic amorphous fiber with an as-drawn diameter of about 10 ¿m (AMFD) exhibits a unique B-H loop in the MHz range. We determined that if the AMFD core is used at about 1 kG at 1 MHz, the core loss is extremely low (1.7 J/m³), although the permeability is also low (200). We designed and fabricated a magnetic head employing an AFMD core for magneto-optical recording by magnetic field modulation, with an AMFD bundle center core piece 1 mm in diameter. Comparison of the AMFD core head with a conventional ferrite head shows that losses in the former are about 60% of those in the latter, under the same conditions of magnetic field and inductance.