Thin film magnetic head and production method thereof and magnetic disk drive equipped with this thin film magnetic head

A thin film magnetic head, comprising:

• an under layer formed on a substrate;
• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and
• a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise at least one metal oxide selected from the group consisting of 15 to 60 wt. % ZrO.sub.2, 15 to 60 wt. % HfO.sub.2, 10 to 60 wt. % TiO.sub.2, 5 to 70 wt. % Ta.sub.2 O.sub.5, 5 to 70 wt. % Nb.sub.2 O.sub.5, 5 to 40 wt. % CeO.sub.2, and 10 to 40 wt. % SiO.sub.2, and the balance of Al.sub.2 O.sub.3, whereby the thin film magnetic head is provided with reduced pole tip recession as compared to a magnetic head having an under layer, magnetic flap film and protective layer consisting of Al.sub.2 O.sub.3.

A thin film magnetic head comprising an under layer formed on a substrate;

• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and have a dissolving rate of 0.1-15 .ANG./min for warm water of pH 6-8 at temperatures 40.degree.-60.degree. C.

A thin film magnetic head comprising an under layer formed on a substrate;

• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and have etching rate of 1-100 nm/hr for deionized water of resistivity larger than 10 M.OMEGA.cm.

A thin film magnetic head comprising an under layer formed on a substrate;

• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and have etching rate of 1-100 nm/hr for applying liquid of pH 6-8 and for removing liquid of pH 9-11.

A thin film magnetic head comprising an under layer formed on a substrate comprising a sintered material;

• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer are each a sputtered film comprising at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and is substantially the same as said substrate in dissolving rate for deionized water.

A thin film magnetic head comprising an under layer formed on a substrate comprising a sintered material;

• a bottom magnetic core film formed on aid under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer are each a sputtered film comprising at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and is different from said substrate in dissolving rate by 0.1-15 .ANG./min.

A thin film magnetic head comprising an under layer formed on a substrate;

• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise a material different from a material of said substrate, and said under layer, said magnetic gap film, and said protective layer comprise at least 60 wt. % Al.sub.2 O.sub.3 and 5 to 40 wt. % metal oxide having an oxidation number larger than that of Al.sub.2 O.sub.3, and have substantially the same dissolving rate as said substrate.

A thin film magnetic head, comprising:

• an under layer formed on a substrate;
• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and
• a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film, and said protective layer comprise 5 to 60 wt % ZrO.sub.2, 2 to 10 wt % Y.sub.2 O.sub.3 and the balance Al.sub.2 O.sub.3, whereby the thin film magnetic head is provided with reduced pole tip recession as compared to a magnetic head having an under layer, magnetic gap film and protective layer consisting of Al.sub.2 O.sub.3.

A thin film magnetic head, comprising:

• an under layer formed on a substrate;
• a bottom magnetic core film formed on said under layer;
• a top magnetic core film which contacts said bottom magnetic core film on one side and which is opposed to said bottom magnetic core film via a magnetic gap film on the other side;
• and
• a protective layer formed on said top magnetic core film;
• wherein said under layer, said magnetic gap film and said protective layer comprise 5 to 60 wt % ZrO.sub.2, 2 to 10 wt % of at least one of CeO.sub.2 and Y.sub.2 O.sub.3, and the balance Al.sub.2 O.sub.3, whereby the thin film magnetic head is provided with reduced pole tip recession as compared to a magnetic head having an under layer, magnetic gap film and protective layer consisting of Al.sub.2 O.sub.3.