JPH041907A - Magneto-resistance effect type playback head - Google Patents

Abstract

PURPOSE:To prevent the generation of Barkhausen noises and to improve reproducing characteristics by dividing the constituting layer of a magneto-resistance effect element to plural elements of a large aspect ratio by plural magnetic characteristic deteriorated layers. CONSTITUTION:The constituting layer of the magneto-resistance effect element 31 of the magneto-resistance effect type head constituted by disposing a pair of magnetic shield bodies respectively via nonmagnetic insulating layers on both sides of the magneto-resistance effect element 31 joined with drawing-out conductors 14a, 14b at both ends is divided to the plural elements 32a to 32f having the large aspect ratio by the plural magnetic characteristic deteriorated layers 33a to 33e. The magnetostatic energy by the diamagnetic fields generated in the respective divided MR elements 32a to 32f is lowered in this way, by which a monodomain structure is obtd. The generation of the Barkhausen noises is, therefore, prevented and the reproducing characteristics are improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a magnetoresistive read head used in a magnetic disk device or a magnetic tape device, even if the element length of the MR element is shortened, a reflux magnetic domain is generated in the MR element. With the aim of preventing the occurrence of Barkhausen noise caused by domain wall movement and improving reproduction characteristics, a non-magnetic insulating layer is placed on both sides of the magnetoresistive element, which has conductors connected to both ends. In the magnetoresistive read head in which a pair of magnetic shields are arranged, the constituent layers of the magnetoresistive element are divided into a plurality of elements each having a large aspect ratio by a plurality of magnetic property deterioration layers.

[Industrial application field]

The present invention relates to a magnetoresistive reproducing head (hereinafter abbreviated as MR head) used in a magnetic disk device, a magnetic tape device, or the like.

In recent years, with the demand for higher speed and larger capacity of computer systems, there has been an increasing demand for higher speed and higher recording density for magnetic disk devices, which are external storage devices.

Therefore, MR heads are attracting attention as magnetic heads for reproduction because they can provide high reproduction outputs without depending on the speed of the recording medium.

In such an MR head, when the aspect ratio of the magnetoresistive element (hereinafter referred to as MR element) becomes smaller due to higher track density, the demagnetizing field within the element becomes stronger and the magnetic domain structure of the element becomes unstable. Reproduction characteristics tend to deteriorate. Therefore, there is a need for an MR head with good reproduction characteristics that maintains the magnetic domain structure stably without increasing the demagnetizing field within the element even if the aspect ratio of such an MR element becomes small.

[Conventional technology]

The conventional MR head has Cu, Aj!, on both ends, as shown in the schematic perspective view of the main part in FIG. A drawer conductor 14a consisting of, etc.
Non-magnetic insulating layers 12 made of 5i (h, etc.) are placed on both sides of the MR element 13 made of Ni-Fe to which 14b is bonded.
a.

A magnetic silt body 11 made of Ni-Zn ferrite or the like and a shield magnetic layer 15 made of Ni-Fe or the like are connected to each other via 12b.
The structure is equipped with.

Then, a sense current is supplied to the MR element 13 through two lead-out conductors 14a and 14b provided at both ends of the MR element 13, and an output detection area 13a of the MR element 13 is supplied.
Reproduction is performed by detecting changes in the signal magnetic field from the recording medium as changes in voltage.

[Problem to be solved by the invention]

By the way, in the conventional MR head as described above, when the element length of the MR element 13 is shortened as the track density of the recording medium becomes higher, an easy axis in the element length direction is formed inside the MR element 13. The demagnetizing field (H
d) becomes strong and the magnetic domain structure of the MR element 13 confines the magnetic flux and reduces the magnetostatic energy induced by the demagnetizing field (Hd). A reflux magnetic domain structure is obtained which is divided into magnetic domains 21, and domain walls 22 are generated at the boundaries of each magnetic domain 21.

Furthermore, the MR element 13 made of the Ni-Fe film generally has non-uniformities such as crystal grain boundaries, lattice defects, and impurity inclusions due to imperfections during film formation. Since the domain walls 22 between the magnetic domains 21 in the element 13 move discontinuously as if caught, the magnetization rotation of each magnetic domain 21 becomes discontinuous, causing Barkhausen noise in the reproduced signal and deteriorating the reproduction characteristics. was there.

In view of the above-mentioned conventional problems, the present invention has a structure in which a reflux magnetic domain does not occur in the MR element even if the element length of the MR element is shortened, thereby preventing the occurrence of Barkhausen noise caused by domain wall movement. It is an object of the present invention to provide a magnetoresistive reproducing head with good reproducing characteristics.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a pair of magnetic shields each disposed on both sides of a magnetoresistive element having a lead-out conductor connected to both ends via a non-magnetic insulating layer. In the magnetoresistive reproducing head, the constituent layers of the magnetoresistive element are divided into a plurality of elements each having a large aspect ratio by a plurality of magnetic property deterioration layers.

[For production]

In the present invention, for example, electron beams or laser beams are selectively irradiated at predetermined intervals in the length direction of the MR element constituent layer in the MR head to thermally degrade the magnetic properties, or impurities are implanted by ion implantation. By providing a plurality of magnetic property deterioration layers whose magnetic properties have been degraded by selectively injecting them at predetermined intervals, and by dividing the MR element into a plurality of elements with large aspect ratios, each divided MR element has Since it becomes possible to lower the magnetostatic energy due to the generated demagnetizing field and obtain a single magnetic domain structure, the generation of Barkhausen noise is prevented and the reproduction characteristics are improved.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of essential parts showing an embodiment of an MR element in an MR head according to the present invention.

In the figure, reference numeral 31 denotes an MR element made of a Ni-Fe film with lead-out conductors 14a and 14b made of Cu, ^1, etc. bonded to both ends. A plurality of magnetic property deterioration layers 33 whose magnetic properties have been thermally degraded by selective irradiation with a laser beam are provided.

Specifically, as shown in the partially enlarged perspective view of FIG. 2, an MR element 31 made of a Ni-Fe film is selectively irradiated with, for example, an electron beam or a laser beam at predetermined intervals in the length direction. Curie (Cu) of the Ni-Fe film
A plurality of magnetic property deterioration layers 33a~ whose magnetic properties are deteriorated by partially heating to a temperature (460°C) higher than the rie) point.
33e, or by implanting impurity ions such as protons (H ions or helium (He') ions) at predetermined intervals in the length direction of the MR element 31 made of the same Ni-Fe film. By providing a plurality of magnetic property deterioration layers 33a to 33e whose magnetic properties are partially degraded by selective implantation, the MR element 31 is formed into a plurality of element portions 32a to 33e having a large aspect ratio.
The configuration is divided into 32f.

By providing an MR head that incorporates the MR element 31 having such a plurality of divided element parts 32a to 32f, each of the divided MR element parts 32a to 32
Since each of f has a single magnetic domain structure, generation of Barkhausen noise is prevented and distortion of the reproduced waveform is also eliminated, so that the reproduction characteristics are improved.

In the above embodiment, an example of a self-bias type MR head using a two-terminal type MR element has been described, but the present invention is not limited to such a bias type MR head. Similar effects can be obtained when applied to various bias type MR heads using two-terminal MR elements.

〔Effect of the invention〕

As is clear from the above description, according to the magnetoresistive read head according to the present invention, even if the element length of the MR element is shortened in response to the increase in trunk density, the generation of freewheeling magnetic domains and the bulk This has practical effects such as preventing the occurrence of Hausen noise and improving the reproduction characteristics of the recording medium.

Figure 4 shows MR in a conventional magnetoresistive read head.
FIG. 3 is a partially enlarged perspective view for explaining problems with the device.

In FIGS. 1 and 2, 14a and 14b are lead-out conductors, 31 is an MR element, and 32
a to 32f are divided MR element parts, 33a to 33e
indicate layers with deteriorated magnetic properties.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts showing an embodiment of the MR element in the magnetoresistive read head according to the present invention, and FIG. 2 is a perspective view for explaining the MR element in the magnetoresistive read head according to the present invention. A partially enlarged perspective view; FIG. 3 is a schematic perspective view of the main parts of a conventional magnetoresistive read head;

Claims (3)

[Claims] (1) In a head configuration in which a pair of magnetic shields are disposed on both sides of a magnetoresistive element (31) with lead-out conductors (14a, 14b) connected to both ends thereof, with a nonmagnetic insulating layer interposed therebetween, the magnetoresistive effect described above is achieved. A magnetoresistive reproducing head characterized in that a constituent layer of an element (31) is divided into a plurality of elements (32a to 32f) having a large aspect ratio by a plurality of magnetic property deterioration layers (33a to 33e). (2) The magnetoresistive effect according to claim 1, wherein the magnetic property deteriorated layer (33a to 33e) is a layer in which a part of the constituent layers of the magnetoresistive element (31) has been deteriorated by heat treatment. mold playback head. (3) The magnetoresistance according to claim 1, wherein the magnetic property deteriorated layer (33a to 33e) is a layer in which a part of the constituent layer of the magnetoresistive element (31) is deteriorated by ion implantation. Effect type playback head.