PURPOSE: To improve the performance of the magnetic head dealing with high- density recording by using a tempered glass member having the coefft. of thermal expansion to the extent of receiving 100 to 160kg/cm2 compressive stress from a core for the magnetic head.
CONSTITUTION: The compsn. of the ferrite constituting the core material 1 of the magnetic head is specified to a range of 5 to 56% Fe2O3, 18 to 20% ZnO and 26 to 28% MnO as a mol%. The tempered glass member 3 is sealed by heating on the core material 1 and is mirror-finished. The material having (95 to 101)×10-7/°C coefft. of thermal expansion is used for the member 3. The glass having the compressive stress in the 100 to 160kg/cm2 range is used for the member 3. Cracks increases approximately to ≥15% if the compressive stress exceeds 160kg/cm2. Such percentage is nonnegligible for production. The major cause for the cracking lies in the application of tensile stresses on the core material 1 and the consequent fracture of the core material 1. The output of the magnetic head for high-density recording is increased by using such member 3.
IKEDA MASAKI
YOSHIDA AKIHIKO
