Combination magnetoresistive/inductive thin film magnetic head and its manufacturing method

A combination thin film magnetic head comprising:

• a magnetoresistive element layer;
• a main lead layer for supplying a sensing current to said magnetoresistive element layer;
• a lower core layer formed on the main lead layer with an insulation layer therebetween and having both a leading-side core function of an inductive head and an upper shielding function of a reading head;
• an upper core layer having an end opposed to the lower core layer with a magnetic gap therebetween in the portion opposite to a recording medium, with the other end magnetically connected to the lower core layer;
• and
• a coil layer for applying a magnetic field to both core layers;
• wherein said lower core layer is expressed by the composition formula Fe.sub.a M.sub.b O.sub.c wherein M is at least one element selected from Al, Si, Hf, Zr, Ti, V, Hb, Ta, W, Mg and the rare earth elements, wherein when said lower core layer is made of an Fe.sub.a M.sub.b O.sub.c alloy, in a ternary diagram of the Fe.sub.a M.sub.b O.sub.c alloy in which the composition ratios of element Fe, element M and element O are shown on the respective sides, the composition ratios a, b and c (atomic %) are in the range surrounded by the following eight points:
• C (Fe:M:O)=(57.5:9.0:33.5)
• D (Fe:M:O)=(63.3:4.8:31.9)
• E (Fe:M:O)=(75.3:4.0:20.7)
• F (Fe:M:O)=(76.3:5.0:18.7)
• G (Fe:M:O)=(75.0:6.7:18.3)
• H (Fe:M:O)=(70.0:9.0:21.0)
• I (Fe:M:O)=(57.4:13.0:29.6)
• K (Fe:M:O)=(67.5:6.7:25.8).

A combination thin film magnetic head comprising:

• a magnetoresistive element layer;
• a main lead layer for supplying a sensing current to said magnetoresistive element layer;
• a lower core layer formed on the main lead layer with an insulation layer therebetween and having both a leading-side core function of an inductive head and an upper shielding function of a reading head;
• an upper core layer having an end opposed to the lower core layer with a magnetic gap therebetween in the portion opposite to a recording medium, with the other end magnetically connected to the lower core layer;
• and
• a coil layer for applying a magnetic field to both core layers;
• wherein said upper core layer is expressed by the composition formula Fe.sub.a M.sub.b (T+O).sub.c wherein M is at least one element selected from Al, Si, Hf, Zr, Ti, V, Hb, Ta, W, Mg and the rare earth elements, and T is either of the elements B and C.

A combination thin film magnetic head comprising:

• a magnetoresistive element layer;
• a main lead layer for supplying a sensing current to said magnetoresistive element layer;
• a lower core layer formed on the main lead layer with an insulation layer therebetween and having both a leading-side core function of an inductive head and an upper shielding function of a reading head;
• an upper core layer having an end opposed to the lower core layer with a magnetic gap therebetween in the portion opposite to a recording medium, with the other end magnetically connected to the lower core layer;
• and
• a coil layer for applying a magnetic field to both core layers;
• wherein said lower core layer is expressed by the composition formula Fe.sub.a M.sub.b (T+O).sub.c wherein M is at least one element selected from Al, Si, Hf, Zr, Ti, V, Hb, Ta, W, Mg and the rare earth elements, and T is either of the elements B and C, wherein when said lower core layer is made of an Fe.sub.a M.sub.b (T+O).sub.c alloy, in a ternary diagram of the Fe.sub.a M.sub.b (T+O).sub.c alloy in which the composition ratios of element Fe, element M and element (T+O) are shown on the respective sides, the composition ratios a, b and c (atomic %) are in the range surrounded by the following eight points:
• C (Fe:M:T+O)=(66.8:4.0:29.2)
• D (Fe:M:T+O)=(74.0:5.0:21.0)
• E (Fe:M:T+O)=(75.0:7.5:17.5)
• F (Fe:M:T+O)=(72.3:10.5:17.2)
• G (Fe:M:T+O)=(62.6:13.7:23.7)
• I (Fe:M:T+O)=(57.5:14.5:28.0)
• J (Fe:M:T+O)=(57.8:10.2:32.0)
• K (Fe:M:T+O)=(58.7:4.4:36.9).

A combination thin film magnetic head comprising:

• a magnetoresistive element layer;
• a main lead layer for supplying a sensing current to said magnetoresistive element layer;
• a lower core layer formed on the main lead layer with an insulation layer therebetween and having both a leading-side core function of an inductive head and an upper shielding function of a reading head;
• an upper core layer having an end opposed to the lower core layer with a magnetic gap therebetween in the portion opposite to a recording medium, with the other end magnetically connected to the lower core layer;
• and
• a coil layer for applying a magnetic field to both core layers;
• wherein at least one of said upper core layer and lower core layer is made of a soft magnetic alloy expressed by the composition formula Ni.sub.a Fe.sub.b X.sub.c wherein X is either of the elements Mo and S, and the composition ratios a, b and c by atomic % satisfy the following relations:
• 44.ltoreq.a.ltoreq.54, 42.5.ltoreq.b.ltoreq.54, 0.ltoreq.c.ltoreq.4, and a+b+c=100.

A combination thin film magnetic head comprising a reading head having a magnetoresistive element layer, and a writing head having an inductive head and laminated on the reading head;

• wherein the reading head comprises a lower shielding layer, the magnetoresistive element layer formed on the lower shielding layer with a lower insulation layer therebetween, a main electrode layer for applying a sensing current to the magnetoresistive element layer, and an upper shielding layer formed on the magnetoresistive element layer and the main electrode layer with an upper insulation layer therebetween, and serving as a lower core layer of the inductive head;
• and
• the writing inductive head comprises the upper shielding layer serving as the lower core layer, an upper core layer having an end opposed to the upper shielding layer with a magnetic gap therebetween in the portion opposite to a recording medium, with the other end magnetically connected to the upper shielding layer, and a coil layer for applying a magnetic field to the upper shielding layer and the upper core layer, the lower shielding layer being made of a material selected from the following materials:
• (A) materials represented by the composition formula Ni.sub.a Fe.sub.b X.sub.c wherein X represents at least one element of Nb, Mo and S, and the composition rations by atomic % are in the following ranges:
• 78.8.ltoreq.a.ltoreq.82.4 at %
• 11.ltoreq.b.ltoreq.13.8 at %
• 5.5.ltoreq.c.ltoreq.8.8 at %
• a+b+c=100 at %
• (B) materials having an amorphous structure and represented by the composition formula Co.sub.a Zr.sub.b Nb.sub.c wherein the composition ratios by atomic % are in the following ranges:
• 78.ltoreq.a.ltoreq.80 at %
• 6.ltoreq.b.ltoreq.7 at %
• 1.ltoreq. c.ltoreq.14 at %
• 0.4<(c/c+b)<0.8
• a+b+c=100 at %
• (C) materials having an amorphous structure and represented by the composition formula Co.sub.a Hf.sub.b Ta.sub.c wherein the composition ratios by atomic % are in the following ranges:
• 79.ltoreq.a.ltoreq.81 at %
• 7.6.ltoreq.b.ltoreq.17.6 at %
• 3.8.ltoreq.c.ltoreq.13.2 at %
• 0.4<(c/c+b)<0.8
• a+b+c=100 at %.