JPH087234A - Magnetoresistance element - Google Patents

Abstract

PURPOSE: To enhance head efficiency and reduce noise by a method wherein a magneto resistive element of a magneto resistive type thin film head is formed to be in a 'C' shape and a lateral bias applying wire is arranged in a nonmagnetic gap positioned rearwardly. CONSTITUTION: When a magneto resistive element is formed employing a magnetic resistance type thin film magnetic head, a magnetic resistor element 1 is formed to be in a 'C' shape like a closed circuit, so that a ratio of a length to a width (H) of the magneto resistive element is sufficient in order to reduce a diamagnetic field in the element. A bias coil 2 serving as a lateral bias applying wire is arranged in a nonmagnetic gap rearwardly of the 'C'-shaped magneto resistive element 1 so as to vary a bias magnetic field, thereby applying the magneto resistive element 1 from a lateral magnetic field by a bias current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element, more specifically, a "C" magnetically resembling a closed circuit in a magnetoresistive element of a magnetoresistive thin film head used in an information recording apparatus. By forming a lateral bias applying line (bias loop or bias coil) in the non-magnetic gap located at the rear, the Baruhausen noise (Barkhausen n
oise: Multi-domain (multi) that causes noise during playback
domain: generated by a demagnetizing field existing in the lateral direction of the element) to improve the efficiency of the head and reduce noise.

[0002]

2. Description of the Related Art In general, in accordance with higher magnetic recording density and higher performance of information recording devices, a magnetic head is more preferably a thin film magnetic head instead of a conventionally used ferrite head or MIG head. In particular, the demand for thin-film magnetic storage type heads using magnetoresistive elements, which have particularly excellent reproducing characteristics, has recently increased rapidly in the same industry field, but the magnetoresistive elements are due to the magnetic domain structure of multiple magnetic domains existing in the element. Due to the noise characteristic of the generated Barkhausen noise during playback, the main research target was to improve head efficiency and reduce noise during head design.

As shown in FIG. 2, the magnetoresistive element of the magnetic head according to the prior art is a thin film of FeMn alloy based on both sides of the magnetoresistive element 11 in order to form a single magnetic domain in the lateral direction of the linear magnetoresistive element. The replacement patterns 12 and 13 are installed (shown in FIG. 2A).

On the other hand, US Pat. No. 4,663,
No. 685 is a reproducing head in which an antiferromagnetic thin film is vapor-deposited on both ends of a magnetoresistive element to apply a bias in the lateral direction. The lateral bias changes the magnetic domain state at both ends of the element to a single domain state. Is sufficient to maintain a single domain state in the central part of the device, and a central part of the device is longitudinally biased by an isolated conductive element. By disposing the element), it is disclosed that the generation of the bulk Heisen noise of the magnetoresistive element is reduced without reducing the sensitivity of the magnetoresistive element.

US Pat. No. 5,159,5
No. 11 is a head composed of a magnetoresistive element and a conductor for applying a bias in the lateral and vertical directions of the element, and the magnetoresistive element 21 is formed in a "1" shape,
It is disclosed that the bias coils 22 and 23 are installed at both ends of the magnetoresistive element 21 so that the magnetoresistive element 21 can be maintained in a single magnetic domain state, so that generation of Barkhausen noise can be reduced and track density can be increased ( Figure 2
It shows in (b). ).

[0006]

However, according to the conventional magnetoresistive element shown in FIG. 2, in the one shown in FIG. 2A, the FeMn alloy is corroded and the reliability of the magnetoresistive element is lowered. The problem and the length (l ₁ ) vs. width (1 ₁ ) of the device which is related to the increase of the cross-talk effect from the adjacent track in order to reduce the lateral demagnetization field in the magnetoresistive device. Although the ratio of h ₁ ) must be sufficiently large, the performance of the magnetoresistive head deteriorates due to the influence of the lateral bias magnetic field in the face of the structural limit point, and the magnetoresistive element 11 and the antiferromagnetic pattern 12, Due to the strong temperature dependence of the exchange effect between 13, Barkhausen noise increases with increasing ambient temperature.

A bias applying line (biasing loop; biasing lo) is provided near both ends of the linear magnetoresistive element 21.
op) 22 and 23 can be installed to change the magnetic field (shown in FIG. 2 (b)), but this also cannot increase the ratio of length (l ₂ ) to width (h ₂ ) due to structural characteristics. Therefore, the effect of demagnetizing field cannot be completely removed, and the number of steps for installing the bias applying lines 22 and 23 at both ends of the magnetoresistive element 21 increases. It was Further, there is a problem that the use of the bias applying lines 22 and 23 causes the magnetoresistive element 21 to bend from the air-holding surface of the magnetoresistive head, thereby deteriorating its performance.

According to the magnetoresistive element of the former United States patent, there is a problem that the anisotropic magnetic field in the element increases and the sensitivity decreases.

According to the magnetoresistive element of the latter US patent, the anisotropic magnetic field in the element is large and the sensitivity is low, so that it cannot be used as a magnetoresistive element in a shielded magnetoresistive head. There was a point.

[0010]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to prevent a magnetoresistive element of a thin film magnetic head from being affected by a lateral demagnetizing field. In order to minimize it, it is formed into a “C” shape that resembles a closed circuit, and a vertical bias application line is installed in the rear non-magnetic gap to suppress not only Barkhausen noise when designing the head. An object of the present invention is to provide a magnetoresistive element capable of improving head efficiency and manufacturing yield.

[0011]

The feature of the present invention for achieving the above object is that a magnetoresistive element in a magnetoresistive thin film head is formed in a "C" shape so as to reduce the demagnetizing field within the element. That is, a bias applying line (for example, a bias loop or a bias coil) is installed in the non-magnetic gap behind the magnetoresistive element.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element according to the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of a magnetoresistive element according to an embodiment of the present invention. In forming a magnetoresistive element for use in a magnetoresistive thin film magnetic head, which has recently been in rapid demand for information recording devices, The magnetoresistive element 1 is formed in a "C" shape resembling a closed circuit so that the ratio of the length to the width (H) of the magnetoresistive element 1 is sufficient to reduce the demagnetization field in the "C" shape. A magnetic field in the lateral direction due to a bias current is applied to the magnetoresistive element 1 by installing a bias coil 2 as a lateral bias applying line in the rear nonmagnetic gap of the magnetoresistive element 1 and varying the bias magnetic field. It is configured to.

When the demagnetizing field in the lateral direction within the magnetoresistive element 1 is removed, the element maintains a single domain state, and as a result, the Barkhausen noise is extinguished. In order to reduce the demagnetizing field in the lateral direction of the magnetoresistive element,

In the equation (where, Hd: demagnetizing field, Ms: element saturation magnetization value, h: element width, 1: element length), the length (l) of the magnetoresistive element versus the width (h 2) or 2) Design the magnetoresistive element into a "C" shape similar to a closed circuit so that it is magnetically continuous so that it is sufficiently magnetized at the edges of the element. Or 3) adopting an exchange biasing method, or 4) adopting a barber pole conductor.

[0016]

As described above, the magnetoresistive element according to the present invention is formed in a "C" shape so that the length-to-width ratio of the magnetoresistive element is sufficient, and magnetically resembles a closed circuit. By forming a bias (current) application line in the non-magnetic gap at the rear of the magnetoresistive element formed in an annular shape,
Improves head efficiency by suppressing the generation of multi-domains in the center sensing part of the element, which is the cause of bulk Heisen noise generated during reproduction, and applies a lateral bias line only around the rear gap of the magnetoresistive element. Is installed to reduce the number of manufacturing steps, which has an excellent effect of improving the productivity in designing the head.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a magnetoresistive element according to an embodiment of the present invention.

2A and 2B are explanatory views of a magnetoresistive element according to a conventional technique in which an antiferromagnetic exchange pattern is formed at both ends of the element, and FIG. 2B is a longitudinal bias coil at both ends of the element. FIG. 7 is an explanatory view of what is formed adjacent to the exchange pattern.

[Explanation of symbols]

 1 Magnetoresistive element 2 Bias application line (bias coil)

Claims (1)

[Claims] 1. In a magnetoresistive element in a magnetoresistive thin film, a non-magnetic gap located at the rear of the magnetoresistive element (1) formed in a "C" shape in order to reduce a demagnetizing field within the element. A magnetoresistive element, characterized in that a bias application line (2) in the direction is installed.