Abstract: A gap layer of a thin-film magnetic head is formed of NiP. The P content of the NiP gap layer is controlled to be within the range of 11 mass percent to 14 mass percent so that the gap layer is nonmagnetic.

Abstract: An upper shield layer includes a Ni—Fe alloy underlying film formed by sputtering deposition, and a Ni—Fe alloy plating film formed on the underlying film by electroplating. The Fe composition ratio distribution of the upper shield layer in the thickness direction ranges from 17 to 19% by weight.

Abstract: A lower core layer and upper core layer are conventionally made of a CoFeNi alloy or the like having a relatively high saturation magnetic flux density, but these layers have the problem of increasing an eddy current loss due to the low resistivity of the CoFeNi alloy with a higher recording frequency. In the present invention, a lower core layer and/or upper core layer is made of a CoFeNiX (X is S, P, or the like) alloy, which has a high saturation magnetic flux density, high resistivity, and low coercive force, as compared with the CoFeNi alloy. Therefore, it is possible to manufacture a thin film magnetic head capable of complying increases in recording density and recording frequency in the future.

Abstract: A lower core layer and upper core layer are conventionally made of a CoFeNi alloy or the like having a relatively high saturation magnetic flux density, but these layers have the problem of increasing an eddy current loss due to the low resistivity of the CoFeNi alloy with a higher recording frequency. In the present invention, a lower core layer and/or upper core layer is made of a CoFeNiX (X is S, P, or the like) alloy, which has a high saturation magnetic flux density, high resistivity, and low coercive force, as compared with the CoFeNi alloy. Therefore, it is possible to manufacture a thin film magnetic head capable of complying increases in recording density and recording frequency in the future.

Abstract: A thin film magnetic head includes an upper core layer and a lower core layer which are made of an Fe--M--O alloy, an Fe--M--T--O alloy or an NI--Fe--X alloy so that the upper core layer has a high saturation magnetic flux density, low coercive force and high resistivity, and the lower core layer has a lower saturation magnetic flux density than the upper core layer, low coercive force, high resistivity, and a low magnetostriction constant. Also the lower core layer is formed so that the thickness gradually decreases toward both side ends, and a gap layer can be formed on the lower core layer to have a uniform thickness. Since the lower core layer is formed by sputtering, a material having excellent soft magnetic material can be used, thereby enabling recording at high frequency.