JP3240050B2 - Floating magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a recording device such as an HDD, and more particularly to a levitation type magnetic device provided with a slider whose levitation amount does not largely change even if the atmospheric pressure in the outside of the magnetic recording device fluctuates. About the head.

[0002]

2. Description of the Related Art A magnetic disk drive (also referred to as an HDD) used in a computer or the like utilizes a viscous flow of air (hereinafter, referred to as an air flow) generated by rotation of a magnetic disk (magnetic recording medium). It employs a method in which the slider of the magnetic head floats above the magnetic disk. Various configurations have been considered for the medium facing surface of the slider that receives this air flow. For example, Japanese Patent Application Laid-Open No. 7-14139 discloses a configuration of a slider in which an angle of a wall connecting a positive pressure surface and a negative pressure groove is acute. Japanese Patent Application Laid-Open No. Hei 7-21720 discloses a configuration of a slider in which a groove having a flat bottom surface is provided in a medium facing surface.

FIG. 6 is a side view showing an example of a conventional floating magnetic head. This floating magnetic head is a slider 103
This is an assembly provided with a spring arm 105 via a gimbal 104. The slider 103 has a medium facing surface 106. The medium facing surface has an inflow end for receiving the airflow and an outflow end for the airflow to exit (the direction of the airflow is indicated by an arrow in the figure). In the figure, the outflow end corresponds to the periphery of the MR head 102. To elaborate,
The inflow end side refers to a side into which an air flow generated by the rotation of the magnetic disk when the slider flies above the rotating magnetic disk flows. The outflow end side is a side from which the airflow that has passed along the medium facing surface of the slider flows out. The spring arm 105 is driven by a positioning means such as a voice coil motor (not shown). Further, the medium facing surface 106 (also referred to as an air bearing surface or an ABS surface) of the slider is pressed against the magnetic disk 109 by the force of the spring of the spring arm 105. Contact. In order to avoid collision due to stoppage of disk rotation, a method of moving a slider from above a magnetic disk before stoppage may be adopted.

[0004] The slider has a medium facing surface on the side facing the magnetic disk. Generally, a side rail having a shape along the longitudinal direction of the slider is used as a medium facing surface. The MR head is provided at the rear end of the side rail. When the air flow accompanying the rotation of the magnetic disk flows along the medium facing surface of the side rail, the MR head floats with respect to the magnetic disk together with the medium facing surface. The MR head includes a reproducing element for reading data from a magnetic disk using a magnetoresistance effect or a giant magnetoresistance effect, and a recording element for writing data to the magnetic disk.

[0005] The reproduction output of the MR head is very small and may be on the order of microvolts. Therefore, in order to reliably extract a signal serving as data from the reproduced output, it is necessary to reduce noise and prevent the amplitude of the reproduced output signal from decreasing. One of the causes of the reduction in the reproduction output is a fluctuation in the flying height. The flying height is the distance between the medium facing surface near the MR head and the magnetic disk.

If the flying height changes greatly, there arise problems such as a decrease in the reproduction output detected by the MR head and a friction between the MR head and the magnetic disk. It is required to keep the flying height constant, but the flying height of the slider depends on the airflow generated by the rotation of the magnetic disk. Therefore, when the air pressure inside the magnetic recording device changes due to the air pressure outside the magnetic recording device, the flying height of the slider also changes. HDDs that are manufactured in a standard atmospheric pressure area and have no problem even when inspected
When used in a high altitude area or an aircraft where the air pressure is low, the flying height of the slider changes, which may cause fluctuations in the reproduction output. SUMMARY OF THE INVENTION It is an object of the present invention to provide a flying magnetic head in which the flying height does not fluctuate greatly with changes in atmospheric pressure.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a flying magnetic head capable of suppressing fluctuations in flying height even when a hard disk drive is used in a place having a low atmospheric pressure.

[0008]

According to one aspect of the present invention, there is provided a medium facing surface, a step provided at an inflow end of the medium facing surface, and a cavity provided at an outflow end of the step. , The ratio of the depth of the step and the cavity ds / d
c is defined within the range of 0.1 to 0.4, the medium-to
This is a floating magnetic head having a protective film on the opposite surface . The step is a surface having a step between the medium facing surface and the step, and is arranged on the inflow end side of the medium facing surface. The step between the medium facing surface and the step is connected by a slope or a side wall. Further, the cavity is a surface having a step between the medium facing surface,
This is a surface provided closer to the outflow end than the step. Further, it is preferable that the flying magnetic head has a configuration in which the relationship between ds and df is defined as follows. That is, in the present invention, the medium facing surface has a step on the front side and a step on the side surface toward the step, and the medium facing surface has a step on the rear side on the cavity side and the step on the side surface. The ratio dsf / dc of the depth of the step on the rear side is in the range of 0.1 to 0.4, and the ratio ds / dc of the depth of the step on the front side and the depth of the step on the rear side is 0.1. It is assumed to be in the range of 1 to 0.4. In this way, even if the direction of the airflow flowing into the medium facing surface changes, stable flying characteristics can be maintained while suppressing altitude dependence.

Another aspect of the present invention is a flying magnetic head having a step for generating a positive pressure and a step for generating a negative pressure on a medium facing surface, wherein the step for generating a positive pressure and the negative pressure are provided. The floating magnetic head is characterized in that the ratio of the depth of the step at which the turbulence occurs is defined within the range of 0.1 to 0.4, and the protective film is provided on the medium facing surface . Here, the step that generates a positive pressure refers to a step, a steep slope, a convex portion, or the like that becomes a wall for the airflow flowing from the inflow end side of the slider.
The step that generates a negative pressure refers to a step, a dent, a recess, or the like into which the air flow is entrained when viewed from the inflow end side of the slider.

In each of the above inventions, it is desirable that the depth of the cavity is 5 μm or less. The reason for this definition is that if the cavity depth is larger than 5 μm, the negative pressure becomes weak and it becomes difficult to keep the flying height of the slider constant. Further, it is desirable to provide a protective film on the medium facing surface of the slider, the step, the cavity, and the wall surface connecting these. In the present invention, the expression “ds / dc is in the range of 0.1 to 0.4” is equivalent to the relationship of 0.1 ≦ ds / dc ≦ 0.4.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A floating magnetic head according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a graph showing a drop rate with respect to a ratio of a step to a cavity. FIG. 2 is a graph showing the drop rate with respect to the step depth of the slider. 1 and 2 are graphs obtained by simulation. 3 to 5 are views for explaining a floating magnetic head according to an embodiment of the present invention, and include a plan view of a slider viewed from a medium facing surface and a cross-sectional view of the slider.

FIG. 1 is a graph showing the drop rate with respect to the ratio between the step and the cavity. The vertical axis in FIG. 1 is a drop rate, a normal flying height and an altitude of 3000 m.
Represents the ratio of the flying height at. That is, when the drop rate is 0.9, it indicates that the flying height has decreased by 10% in accordance with the decrease in the atmospheric pressure. The drop rate 1.0 is a state in which the flying height is not affected by the atmospheric pressure. The horizontal axis in FIG. 1 is the ratio of the step formed in the slider to the depth of the cavity, and is a numerical value obtained by dividing the step depth ds by the cavity depth dc. Hereinafter, this ratio is represented by ds / dc.

FIG. 1 shows that when ds / dc is smaller than 0.1, the drop rate tends to decrease sharply. When a disturbance other than a change in the atmospheric pressure is applied, the flying height may further decrease. Also, a simulation of the step depth revealed that, as shown in FIG. 2, if the step depth was small, the drop rate was likely to change rapidly. Therefore, in order to suppress the contact between the slider and the magnetic disk due to the decrease in the flying height, the ratio between the step and the depth of the cavity may be set to 0.1 or more. In this way, the flying height does not need to be reduced by more than 15%.

On the other hand, when the drop rate increases (that is, when the flying height increases), there is a problem that the reproduction output of the magnetic head decreases. According to FIG. 1, ds / dc is 0.3
From 0.4 to 0.4, like an inverted triangular data point. Since the strength of the signal magnetic field from the medium is inversely proportional to the square of the distance, even if the flying height increases even slightly, the reproduction output greatly decreases. Therefore, in order to obtain a stable reproduction output, it is desirable to set ds / dc to 0.4 or less. From the above, it was found that the preferred range of ds / dc was in the range of 0.1 to 0.4.

Next, a floating slider according to an embodiment of the present invention will be described with reference to FIG. The flying magnetic head shown in the plan view (a) of FIG. 3 has a step 11, a cavity 12, and a medium facing surface 13 on the medium facing surface of the slider. Provided an MR head 14. Each medium facing surface was arranged as two spaced rails. A sectional view of the plan view (a) taken along the line AB is shown in FIG. The ratio of the depth ds of the step 11 to the depth of the cavity 12 was 0.3. As shown in the drawing, the depth indicates how much the groove is depressed from the medium facing surface 13.
The configuration of the slider, gimbal, and suspension is the same as that of the conventional magnetic head, and is not shown in FIG.

Next, a floating slider according to another embodiment of the present invention will be described with reference to FIG. The floating magnetic head shown in the plan view (a) of FIG. 4 has a step 21 and a cavity 22 on the medium facing surface of the slider, and medium facing surfaces 23R and 23R.
3L and a medium facing surface 27. An MR head 24 was provided at the end of the medium facing surface 27 on the outflow end side. The medium facing surfaces 23R and 23L have a step 23 on the front side facing the step.
a and a step 23b on the side surface, and a step 23c on the rear side facing the cavity. The step 23c forms a two-step surface having a depth ds from the front side of the medium facing surface to the step and a depth dc from the medium facing surface to the cavity. Further, FIG. 2B is a cross-sectional view of the plan view (a) taken along the line CC ′. Step 21 Depth ds and Cavity 2
The ratio of the depth dc of 2 was 0.1. (B) is enlarged to illustrate ds for clarity, but does not show the actual size. The depth is based on the medium facing surfaces 23R and 23L. Further, in the configuration of FIG. 4, the relationship between ds and dc in the CC ′ section is changed to DD ′ in order to suppress the altitude dependence.
Applied to cross sections. Medium facing surface 23 as seen in DD ′ section
In L, the step 22b on the side surface is dsf, the step 23c on the cavity side is dc, and (dsf / dc) = 0.1. In this way, even if the direction of the airflow flowing into the medium facing surface is along one of DD ′ and CC ′, the influence of altitude dependence is small and the flying height can be stabilized. did it. Therefore, it can be seen that this flying magnetic head can be used with a substantially constant flying height for the operation of sequentially reproducing a plurality of data recorded at different positions on the magnetic disk even if the air pressure fluctuates. Was.

Next, a floating slider according to another embodiment of the present invention will be described with reference to FIG. This configuration differs from the configuration in FIG. 4 in that one step having a depth dc is provided between the medium facing surfaces 33R and 33L and the cavity 32, but the other configurations are substantially the same. More specifically, in (a), the slider has a step 31, a cavity 32, medium facing surfaces 33R and 33L, and a medium facing surface 37 on the medium facing surface of the slider. The end on the outflow end side of the medium facing surface 37 has M
An R head 34 was provided. The medium facing surfaces 33R and 33L are
Step 33a on the front side facing the step and step 3 on the side surface
3b and a rear step 33c facing the cavity. The step 33c forms one step surface of a depth dc from the medium facing surface to the cavity. Further, a cross-sectional view of the plan view (a) taken along the line EE ′ is shown in FIG. The ratio ds / dc of the depth ds of the step 31 and the depth dc of the cavity 22 was set to ds / dc = 0.12. Further, the relationship between the step 33b on the side surface and the step 33c on the rear side in the section FF ′ is d.
sf / dc = 0.12. In this way, it was possible to obtain a stable reproduction characteristic by suppressing the atmospheric pressure dependency while moving the slider on the magnetic disk in the same manner as in the configuration of FIG.

The flying magnetic head shown in FIG. 5 is provided with flying surfaces 33R and 33L which are long in the length direction of the slider (direction along EE ') and whose inlet ends are close to each other.
A path is provided between the right floating surface 33R and the left floating surface 33L to directly pass from the step to the cavity. The air bearing surface 37 having the MR element is separated from the other air bearing surfaces 33R and 33L, provided near the outflow end of the slider, and provided with a surface 36 lower than the air bearing surface on the inflow end side. The following configuration can be used as a modification of this embodiment. A configuration in which the shape of the floating surfaces 33R and 33L is shortened in the longitudinal direction to have a substantially square shape or a trapezoidal shape, and a configuration in which a smaller auxiliary floating surface is added to each of the floating surfaces 33R and 33L near the outflow end side. , Air bearing surface 33R, 3
For each of the 3Ls, a configuration in which the width near the center or on the outflow end side is smaller than the width on the inflow end side can be used.

A floating magnetic head according to another embodiment will be described. The medium facing surface of the flying magnetic head was composed of two rails extending in the longitudinal direction of the slider and a crossbar connecting the inflow end sides of the rails. The step is formed on the inflow end side of the medium facing surface with respect to the rail and the crossbar, and is provided in a V-shape. This step serves as an inlet for the flow of air. The depth of the step was 0.4 μm. The cavity was formed in the area surrounded by the rail and the crossbar. 2.0 cavity depth
μm. An MR head was provided on one of the side rails. The configuration of the MR head includes a magnetoresistive element for reading a magnetic signal of a magnetic disk, a magnetic pole for recording a magnetic signal on the magnetic disk, and an exciting coil.

Each of the side rails has the widest portion on the inflow end side, and has a slope or a step at the tip of the widest portion. Further, the side rail has a narrowest portion substantially at the middle portion, and the narrow portion is retreated inward from the side edge. The narrowest part is substantially parallel, is inclined with respect to the longitudinal direction of the slider, and is inclined with respect to the side edge. This inclination angle is preferably about 2 to 10 °. The width of the narrowest portion is preferably 5% or more and 40% or less of the length of the side rail, and the width of the narrowest portion is 50% or less, preferably 25% or less of the width of the side rail. is there.

The above-mentioned slider was placed with the medium facing surface including the MR head facing the magnetic disk, and the stability of the flying height with respect to atmospheric pressure fluctuation was evaluated. The air flow generated by the rotation of the magnetic disk flows from the step and acts on the surface of the side rail to generate a levitation force, thereby causing the magnetic head to fly. At the same time, a negative pressure was generated by the airflow flowing from the medium facing surface into the cavity, and the slider floated at a certain height (floating amount) in balance with the positive pressure. When the air pressure inside and outside the magnetic disk device was lowered, recording and reproduction of the magnetic head could be executed without suddenly decreasing the flying height.

Another embodiment of the present invention will be described. In the above embodiment, the protective film is provided only on the medium facing surface in order to suppress the abrasion due to the contact between the slider and the magnetic disk due to the decrease in the flying height. However, if the protective film is provided only on the medium facing surface, the damage of the end of the protective film on the injection end side is accelerated. Therefore, in the present embodiment, the protective film of diamond-like carbon is provided as a continuous film not only on the medium facing surface, but also on both the medium facing surface and the step and on the wall surface of the step between them. The structure of this protective film is such that a silicon base film is provided between diamond-like carbon and the slider.
One having a layer structure and one having a diamond-like carbon single layer could be used.

[0023]

As described above, according to the present invention, it is possible to provide a floating magnetic head which is hardly affected by changes in atmospheric pressure.

[Brief description of the drawings]

FIG. 1 is a graph showing a drop rate with respect to a ratio of a step and a cavity.

FIG. 2 is a graph showing a drop rate with respect to a step depth of a slider.

FIG. 3 is a diagram illustrating a medium facing surface of a floating slider according to the present invention.

FIG. 4 is a view illustrating a medium facing surface of another floating slider according to the present invention.

FIG. 5 is a diagram illustrating a medium facing surface of another floating slider according to the present invention.

FIG. 6 is a side view of a conventional floating slider.

[Explanation of symbols]

11, 21, 31 steps, 12, 22, 32 cavities, 13 medium facing surface, 14 M
R head, 23R, 23L medium facing surface, 33R,
33L medium facing surface, 23a, 33a step on front side,
23b, 33b Side step, 23c, 33c Back step, 24, 34 MR head, 26 27 deeper surface, 36 37 deeper surface, 27
Medium facing surface with MR element, 37 Medium facing surface with MR element.

Claims (3)

(57) [Claims] 1. A medium facing surface, a step provided on an inflow end side of the medium facing surface, and a cavity provided on an outflow end side from the step, wherein a ratio ds / d of a depth of the step and the cavity is provided. A floating magnetic head , wherein dc is defined in a range of 0.1 to 0.4, and a protective film is provided on the medium facing surface . 2. A floating magnetic head having a step for generating a positive pressure and a step for generating a negative pressure on a medium facing surface, wherein the step for generating a positive pressure and the depth of the step for generating a negative pressure are provided. the ratio is defined within the range of 0.1 to 0.4, the medium-to
A floating magnetic head having a protective film on an opposite surface . 3. The floating magnetic head according to claim 1, wherein a depth of the cavity or a depth of a step for generating the negative pressure is 5 μm or less. .