Magnetic head with tape contacting guard surface and pole tips of similar ferrite materials

Claim 1

A magnetic head comprising head-tips of a magnetic ferrite material having a coupling gap for coupling thereof with a magnetic tape record medium and a guard member adjacent said head-tips, the head-tips and guard member having substantially flush tape contact surfaces disposed for contact with the magnetic tape record medium, said head-tips and said guard member both containing as a major constituent on a mol percent basis iron oxide, and both containing as a further substantial constituent zinc oxide, the guard member being formed of a sintered ferrite material having a substantially greater mol percent of zinc oxide than said head-tips such that the reluctance of the leakage paths from the head-tips to the guard member is substantially greater than the reluctance of the coupling gap, but the compositions of the ferrite materials of the head-tips and guard member being sufficiently similar that (1) the hardness of the tape contact surface of the guard member is equal to or slightly less than the hardness of the tape contact surface of the head-tips at the operating temperature of the head-tips under working conditions, and (2) the temperaturehardness characterisTics of the tape contact surfaces of the head-tips and the guard member have substantially the same slope over a substantial temperature range extending at least from room temperature up to said operating temperature, the guard member further including a third constituent in common with said headtips in a substantial amount on a mol percentage basis such that the ferrite material of the guard member contains less than 50 mol percent zinc oxide, but the amount of zinc oxide in the guard member material being more than 30 mol percent so that the Curie temperature is less than room temperature.