JPH0279206A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To provide the good symmetry of upper and lower magnetic characteristics by using two kinds of materials which are different in magnetic annealing temp. to upper and lower cores respectively. CONSTITUTION:The magnetic annealing temp. of the material used for the core part to be formed first is set higher than the magnetic annealing temp. of the material used for the core part to be formed later. Namely, the material having the high magnetic annealing temp. is used for the lower core 2 to be formed first and is subjected to magnetic annealing before formation of the upper core 3. Since the material having the annealing temp. lower than the annealing temp. of the lower core material is used for the upper core 3, the magnetic characteristics of the lower core 2 are not affected at the time of annealing of the upper core 3. The head having the symmetrical magnetic characteristics is obtd. if the magnetization rates of two kinds of the magnetic materials are selected according to the structure of the head.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head for writing and reading magnetic recording, and particularly to a head that has high performance and is easy to manufacture.

[Conventional technology]

Conventional thin-film magnetic heads use the same core material for the upper and lower cores. Incidentally, there is a technique described in Japanese Patent Application Laid-Open No. 62-283406, for example, which is characteristic of the core of this type of device.

[Problem to be solved by the invention]

However, in general, when a magnetic head is manufactured using a thin film process, the internal stress of the upper and lower core materials differs due to the difference in distance between the upper and lower core materials from the substrate, the difference in peripheral materials, etc. This means that
Due to the magnetostrictive properties of the magnetic material, there will be a difference in the magnetic properties of the upper and lower cores. Furthermore, creating the upper and lower cores and electromagnetic coils symmetrically with respect to the magnetic gap using a thin film process complicates the process, so they generally do not have symmetrical shapes.

Despite these asymmetries in shape and internal stress, if you are trying to create a head with symmetrical magnetic properties by using the same material for the upper and lower cores, you will need to arrange the coils in consideration of the magnetostrictive effect, or change the shape of the upper and lower cores. It is necessary to change the magnetic annealing conditions. Generally, internal stress is greater in the lower core, so if the former method is attempted, the process will be complicated. In addition, in the latter method, it is difficult to set the magnetic annealing conditions for the upper core because the magnetic annealing conditions affect the lower core. The purpose is to provide the head.

[Means to solve the problem]

The above object is achieved by using two types of materials with different magnetic annealing temperatures for the upper and lower parts.

Note that the first core portion that is made first generally corresponds to the lower core, and the second core portion that is made later generally corresponds to the upper core.

[Effect]

In other words, a material with a magnetic annealing temperature is used for the lower core, which is formed first, and magnetic annealing is applied before the upper core is created.A material with a lower annealing temperature is used for the upper core compared to the lower core material. Therefore, the magnetic properties of the lower core are not affected during upper core annealing. By selecting the magnetic susceptibilities of the two materials in accordance with the head structure, it is easy to obtain a head with symmetrical magnetic properties.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The lower core 2 shown in the figure is made of F a Co-based magnetic material, and its magnetic annealing temperature is approximately 900°C. Furthermore, due to process considerations, the coil of this head is formed near the upper core, so the lower core uses a material with a higher magnetic susceptibility than the upper core. After forming this magnetic film, it is subjected to magnetic annealing to provide sufficient magnetic susceptibility.

Thereafter, a film is formed using a CoNdZr-based material as the upper core. This material has an annealing temperature of 400℃
Since the annealing temperature is lower than that of the lower core at around ~500° C., the lower core is not adversely affected during magnetic annealing of this material. Also, the magnetic susceptibility is FeC.

Because it is slightly lower than the system, even if it is formed near the coil,
It can have magnetic properties symmetrical to the lower core. Furthermore, even if there is asymmetry due to internal stress or structure, symmetrical magnetic properties can be achieved by changing the annealing conditions of the upper core.

〔Effect of the invention〕

According to the present invention, even if a vertically asymmetrical structure is adopted to simplify the process and the residual stress is also asymmetrical,
By changing the annealing conditions of the core material, a head with symmetrical magnetic properties can be obtained.

[Brief explanation of the drawing]

The figure shows a sectional view perpendicular to the sliding direction of a thin film magnetic head according to an embodiment of the present invention. 1... Board, 2... Lower core, 3... Upper core,
4... Coil, 5... Magnetic gap, 6... Insulating layer, 7... Protective film.

Claims (1)

[Claims] 1. In a thin film magnetic head consisting of two cores (upper and lower), an electromagnetic coil, an insulating layer, and a magnetic gap formed between the cores on a substrate, the magnetic annealing temperature of the material used for the first core part made first is , a thin film magnetic head characterized in that the magnetic annealing temperature is higher than the magnetic annealing temperature of a material used for a second core portion to be manufactured later.