Magnetoresistive head with micro-crystallite shielding layer

An MR head comprising:

• a magnetoresistive layer;
• a bias layer which causes single-magnetic-domain formation in one direction to occur in the magnetoresistive layer;
• and
• two shielding layers for magnetically shielding the upper and lower sides of the magnetoresistive layer, the shielding layers each having a magnetic permeability directed such that, when said MR head is disposed to face a recording medium, the magnetic permeability is higher in a direction normal to a surface of the recording medium than in the direction of the single-magnetic domain formation;
• wherein the shielding layers comprise one or more from the group consisting of Fe--M--C, Fe--M--B, Fe--M--N and Fe--Nb--Si--B--Cu,
• wherein M is one or more of Al, Ta, Hf, Si, Ti, V, Cr, Zr, Nb, Mo, W, Ni and Co, and
• wherein the magnetic permeability in the direction normal to the recording medium with respect to a magnetic frequency of 1 MHz is in the range of 2000 to 4000, and the magnetic permeability in the direction of the single-magnetic-domain formation with respect to the magnetic frequency is less than 500.

An MR head formed as a compound magnetic head for both recording and reproduction comprising at least a lower shielding layer, a magnetoresistive layer, an upper shielding layer, a lower core layer, and an upper core layer sequentially formed on a substrate;

• wherein the lower shielding layer and the upper shielding layer exhibit a magnetic permeability that is higher in a direction normal to a surface of a recording medium which faces the MR head than in a direction of a single-magnetic-domain formation in which the magnetoresistive layer is turned into a single magnetic domain in direction,
• wherein the shielding layers comprise one or more from the group consisting of Fe--M--C, Fe--M--B, Fe--M--N and Fe--Nb--Si--B--Cu,
• wherein M is one or more of Al, Ta, Hf, Si, Ti, V, Cr, Zr, Nb, Mo, W, Ni and Co, and
• wherein the magnetic permeability in the direction normal to the recording medium with respect to a magnetic frequency of 1 MHz is in the range of 2000 to 4000, and the magnetic permeability in the direction of the single-magnetic-domain formation with respect to the magnetic frequency is less than 500.

An MR head formed as a compound magnetic head for both recording and reproduction comprising at least a lower shielding layer, a magnetoresistive layer, a lower core layer which also serves as an upper shielding layer, and an upper core layer are sequentially formed on a substrate;

• wherein the lower shielding layer and the lower core layer also serving as the upper shielding layer exhibit a magnetic permeability that is higher in a direction normal to a surface of a recording medium which faces the MR head than in a direction of a single-magnetic-domain formation in which the magnetoresistive layer is turned into a single magnetic domain in one direction,
• wherein the shielding layers comprise one or more from the group consisting of Fe--M--C, Fe--M--B, Fe--M--N and Fe--Nb--Si--B--Cu,
• wherein M is one or more of Al, Ta, Hf, Si, Ti, V, Cr, Zr, Nb, Mo, W, Ni and Co, and
• wherein the magnetic permeability in the direction normal to the recording medium with respect to a magnetic frequency of 1 MHz is in the range of 2000 to 4000, and the magnetic permeability in the direction of the single-magnetic-domain formation with respect to the magnetic frequency is less than 500.

An MR head formed as a compound magnetic head for both recording and reproduction comprising at least a lower shielding layer, a magnetoresistive layer, a lower core layer which also serves as an upper shielding layer, and an upper core layer are sequentially formed on a substrate;

• wherein the lower shielding layer exhibits a magnetic permeability that is higher in a direction normal to a surface of a recording medium which faces the MR head than in a direction of a single-magnetic-domain formation in which the magnetoresistive layer is turned into a single magnetic domain in one direction,
• wherein the lower shielding layer comprises one or more from the group consisting of Fe--M--C, Fe--M--B, Fe--M--N and Fe--Nb--Si--B--Cu,
• wherein M is one or more of Al, Ta, Hf, Si, Ti, V, Cr, Zr, Nb, Mo, W, Ni and Co, and
• wherein the magnetic permeability in the direction normal to the recording medium with respect to a magnetic frequency of 1 MHz is in the range of 2000 to 4000, and the magnetic permeability in the direction of the single-magnetic-domain formation with respect to the magnetic frequency is less than 500.

An MR head formed as a compound magnetic head for both recording and reproduction comprising at least a lower core layer which also serves as a lower shielding layer, a magnetic gap, and an upper core layer which also serves as an upper shielding layer are sequentially formed on a substrate, with a magnetoresistive layer being provided in said magnetic gap;

• wherein the lower core layer and the upper core layer exhibit a magnetic permeability that is higher in a direction normal to a surface of a recording medium which faces the MR head than in a direction of a single-magnetic-domain formation in which the magnetoresistive layer is turned into a single magnetic domain in one direction,
• wherein the lower core layer and the upper core layer comprise one or more from the group consisting of Fe--M--C, Fe--M--B, Fe--M--N and Fe--Nb--Si--B--Cu,
• wherein M is one or more of Al, Ta, Hf, Si, Ti, V, Cr, Zr, Nb, Mo, W, Ni and Co, and
• wherein the magnetic permeability in the direction normal to the recording medium with respect to a magnetic frequency of 1 MHz is in the range of 2000 to 4000, and the magnetic permeability in the direction of the single-magnetic-domain formation with respect to the magnetic frequency is less than 500.