CN102760449B - The method of test magnetic head resistance to elevated temperatures and device thereof - Google Patents
The method of test magnetic head resistance to elevated temperatures and device thereof Download PDFInfo
- Publication number
- CN102760449B CN102760449B CN201110109622.4A CN201110109622A CN102760449B CN 102760449 B CN102760449 B CN 102760449B CN 201110109622 A CN201110109622 A CN 201110109622A CN 102760449 B CN102760449 B CN 102760449B
- Authority
- CN
- China
- Prior art keywords
- screen layer
- magnetic field
- read head
- output parameter
- air bearing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Magnetic Heads (AREA)
Abstract
The present invention discloses a kind of method testing magnetic head resistance to elevated temperatures, and described magnetic head comprises air bearing face and two screen layers, and described method comprises: with first party to the first magnetic field applying multiple varying strength to described magnetic head, and measure the first output parameter curve; Repeat to apply with second direction the 2nd magnetic field of varying strength, simultaneously with first party to the first magnetic field applying change, and measure multiple 2nd output parameter curve; And judge whether described first output parameter curve and described 2nd output parameter curve exist the change exceeding permissible value, thus filter out bad magnetic head, described first party is to the air bearing face being perpendicular to described magnetic head, and described second direction is perpendicular to the screen layer of described magnetic head. The present invention can filter out the bad magnetic head with not good resistance to elevated temperatures accurately when not heated by magnetic head.
Description
Technical field
The present invention relates to a kind of method testing magnetic head performance, particularly relate to a kind of method testing magnetic head resistance to elevated temperatures. And, the present invention relates to a kind of device testing magnetic head performance, particularly relate to a kind of device testing magnetic head resistance to elevated temperatures.
Background technology
The hard disk drive comprising multiple spinning disk is commonly used in the magnetic media storing data in its magnetic disk surface, and the removable magnetic head comprising read transducer is as reading data from the magnetic rail of magnetic disk surface.
Currently, magnetic resistance (magnetoresistive, MR) read head due to its be embedded with one more the MR element of highly sensitive and be widely used in main flow magnetic head. Magnetic head is before use, a series of performance tests must be carried out, such as resistance to elevated temperatures, dynamic fly height (dynamicflyingheight, DFH) performance, signal to noise ratio (Signal-to-NoiseRatio, SNR) performance, reliability, stability etc. Such as, one has the magnetic head of poor resistance to elevated temperatures, and it can produce a large amount of noises in high temperature environments. If magnetic head has poor SNR performance, damaging the read stability of magnetic head, finally affect the reading performance of magnetic head, therefore, the performance test of magnetic head seems very important and necessary.
Following method is a kind of traditional method testing MR read head. As shown in Figure 1, this MR read head 10 comprises two hard magnetic 112, layer is sandwiched between two hard magnetic 112 MR element 114 and be positioned over MR element 114 and two screen layers 116 on hard magnetic 112 both sides. Known to all, the resistance of MR element can change with the change of external magnetic field, thus the output making MR read head changes. Therefore, apply one have be parallel to screen layer 116 and with the air bearing face 117 (airbearingsurface of MR read head 10, ABS) magnetic field in the direction 19 (being hereafter called " general direction of magnetization ") of 0 �� is become, thus measure the output voltage of MR read head, repeat this kind of operation, then calculating the change of the difference between the highest output voltage and minimum output voltage, the change of this kind of difference is for estimating exporting change whether within a certain permissible value.If exporting change is outside permissible value, then this tested magnetic head is judged as bad magnetic head and is rejected.
The testing method of the general direction of magnetization of above-mentioned employing is widely used in the DFH performance test of magnetic head, SNR performance test and reliability and stability test. But, owing to the performance requriements of magnetic head is more and more higher, therefore adopt general magnetized testing method to be restricted. Resistance to elevated temperatures as magnetic head is tested, and resistance to elevated temperatures is but very insensitive to the magnetization of this kind of general direction of magnetization, and therefore, the method for the resistance to elevated temperatures test of magnetic head is still in the middle of research.
U.S. Patent Publication No.20080049351A1 discloses a kind of method testing magnetic head resistance to elevated temperatures. As shown in Figure 2, the element at magnetic head 21 is formed and arranges a heating unit 35 on surface 2101, thus applies heat and stress to the MR element 32 of magnetic head 21. Specifically, when energized, this heating unit 35 generates heat, in the case, and MR element 32 and material generation thermal expansion around thereof, thus it is raw to make MR element 32 produce a large amount of internal stresss, in addition, also can there is internal modification in MR element 32. Thus, in the case, the noise figure of the output occurring in MR element 32 is measured, and then identifies this tested magnetic head and can produce potential deformation in high temperature environments thus produce noise.
But, due to magnetic head need to repeated test under the hot environment repeatedly changed, therefore temperature selection and control need very accurate. If temperature is too high, then can there is the possibility damaged by good product magnetic head in the process of test.
Again and, aforesaid method is only applicable to be embedded with the magnetic head of heating unit, the method then cannot be adopted to carry out resistance to elevated temperatures test for not having the magnetic head of heating unit.
Therefore, the urgently method of the test magnetic head resistance to elevated temperatures of a kind of improvement, and the method for test magnetic head performance is to overcome above-mentioned defect.
Summary of the invention
It is an object of the present invention to provide a kind of method testing magnetic head resistance to elevated temperatures, it can filter out the bad magnetic head with not good resistance to elevated temperatures when not heated by magnetic head.
Another object of the present invention is to provide a kind of method testing magnetic head performance, and it can detect out the bad magnetic head that the general magnetized traditional method of employing cannot detect completely.
It is yet a further object of the present invention to provide a kind of device testing magnetic head resistance to elevated temperatures, it can filter out the bad magnetic head with not good resistance to elevated temperatures when not heated by magnetic head.
Another object of the present invention is to provide a kind of device testing magnetic head performance, and it can detect out the bad magnetic head that the general magnetized traditional method of employing cannot detect completely.
For reaching above object, the present invention provides a kind of method testing magnetic head resistance to elevated temperatures, described magnetic head comprises air bearing face and two screen layers, and described method comprises: with first party to the first magnetic field applying multiple varying strength to described magnetic head, and measure the first output parameter curve; Repeat to apply with second direction the 2nd magnetic field of varying strength, simultaneously with first party to the first magnetic field applying change, and measure multiple 2nd output parameter curve; And judge whether described first output parameter curve and described 2nd output parameter curve exist the change exceeding permissible value, thus filter out bad magnetic head, described first party is to the air bearing face being perpendicular to described magnetic head, and described second direction is perpendicular to the screen layer of described magnetic head.
As a preferred embodiment, also comprising and apply the 3rd magnetic field with third direction to described magnetic head, described third direction is parallel to described screen layer and becomes 0 �� of angle with described air bearing face.
Goodly, described first party passes to wearing into described air bearing face or from described air bearing face.
Goodly, described screen layer comprises the first screen layer and the 2nd screen layer, and described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
As another preferred embodiment, the scope of the intensity in described first magnetic field and the intensity in described 2nd magnetic field is-800Oe��800Oe.
Goodly, the intensity in described 2nd magnetic field comprises multiple numerical value pair with same absolute.
Goodly, described first output parameter curve and described 2nd output parameter curve are represented by output voltage.
Can selection of land, described first output parameter curve and described 2nd output parameter curve are represented by signal to noise ratio.
Goodly, described change has a maximum transition, and described maximum transition has transition rate, and the transition rate of described permissible value is 8%.
The present invention provides a kind of method testing magnetic head performance, described magnetic head comprises air bearing face and two screen layers, described method comprises: applying the 2nd magnetic field with second direction to described magnetic head, and measure the output parameter of described magnetic head, described second direction is perpendicular to the screen layer of described magnetic head; And repeat to apply the 2nd magnetic field of varying strength, and measure repeatedly output parameter, thus test the performance of described magnetic head.
As a preferred embodiment, also comprising and apply the first magnetic field with first party to described magnetic head, described first party is to the air bearing face being perpendicular to described magnetic head.
As another preferred embodiment, also comprising and apply the 3rd magnetic field with third direction to described magnetic head, described 3rd magnetic head is perpendicular to described screen layer and becomes 0 �� of angle with described air bearing face.
Goodly, described first party passes to wearing into described air bearing face or from described air bearing face.
Goodly, described screen layer comprises the first screen layer and the 2nd screen layer, and described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
Goodly, described first output parameter curve and described 2nd output parameter curve are represented by output voltage.
Can selection of land, described first output parameter curve and described 2nd output parameter curve are represented by signal to noise ratio.
Correspondingly, the present invention provides a kind of device testing magnetic head resistance to elevated temperatures, described magnetic head comprises air bearing face and two screen layers, and described device comprises the first magnetic field applying unit, for first party to the first magnetic field applying multiple varying strength to described magnetic head; First measuring unit, for measuring the first output parameter curve according to described first magnetic field; 2nd magnetic field applying unit, for repeating to apply to described magnetic head the 2nd magnetic field of varying strength with second direction, simultaneously with first party to the first magnetic field applying change; 2nd measuring unit, for measuring multiple 2nd output parameter curve; And judging unit, for judging whether described first output parameter curve and described 2nd output parameter curve exist the change exceeding permissible value, thus filter out bad magnetic head, wherein, described first party is to the air bearing face being perpendicular to described magnetic head, and described second direction is perpendicular to the screen layer of described magnetic head.
The present invention provides a kind of device testing magnetic property, described magnetic head comprises air bearing face and two screen layers, described device comprises: the 2nd magnetic field applying unit, repeats to apply the 2nd magnetic field of varying strength to described magnetic head for the second direction to be perpendicular to described screen layer;And measuring unit, for measuring the output parameter of described magnetic head according to described 2nd magnetic field, thus test the performance of described magnetic head.
Compared with prior art, the present invention applies the 2nd magnetic field to magnetic head to be perpendicular to the second direction of screen layer, and measures the output of magnetic head according to this, and the operation repeatedly repeating this kind of magnetization and measuring, finally filters out bad magnetic head in multiple output curve. The present invention when not heated by magnetic head, at room temperature then can detect out the bad magnetic head of a large amount of noise of potential generation in high temperature environments. Therefore comparing prior art, this kind of testing method is improved. Again and, the present invention can detect out the bad magnetic head that the general magnetized traditional method of employing cannot detect completely, and accuracy of detection is reliable.
By following description and by reference to the accompanying drawings, the present invention will become more clear, and these accompanying drawings are for explaining embodiments of the invention.
Accompanying drawing explanation
Fig. 1 is the partial perspective view of the simplification of MR read head, which show general direction of magnetization.
Fig. 2 is the stereographic map of magnetic head, which show a kind of traditional testing method.
Fig. 3 a is the stereographic map of the magnetic head of the present invention.
Fig. 3 b is the partial perspective view of the simplification of MR read head, which show the magnetic field applying different directions according to one embodiment of the present of invention to MR read head.
Fig. 4 a is the sectional view of MR read head, which show according to the first embodiment of the present invention to MR read head apply first party to and the magnetic field of second direction.
Fig. 4 b is the sectional view of MR read head, which show according to the second embodiment of the present invention to MR read head apply first party to and the magnetic field of second direction.
Fig. 5 is the schema that the present invention tests an embodiment of the method for magnetic head resistance to elevated temperatures.
Fig. 6 a-6i is the graphic representation of a concrete instance, which show the output voltage curve that MR read head under the magnetic field of varying strength is different.
Fig. 7 a-7i is the graphic representation of another concrete instance, which show the output voltage curve that MR read head under the magnetic field of varying strength is different.
Fig. 8 illustrates an embodiment of the device of the test magnetic head resistance to elevated temperatures of the present invention.
Fig. 9 illustrates the schema of an embodiment of the method for the test magnetic head performance of the present invention.
Figure 10 illustrates an embodiment of the device of the test magnetic head performance of the present invention.
Embodiment
Setting forth the present invention's several different most preferred embodiments below with reference to the accompanying drawings, wherein in different figure, identical label represents identical parts. As mentioned above, it is necessary, the essence of the present invention is to provide a kind of method testing magnetic head resistance to elevated temperatures, it applies magnetic field to be perpendicular to the direction of screen layer to magnetic head, thus filters out the defect magnetic head occurring bad performance when using in high temperature environments.
Traditional magnetic head for head-slider generally comprises for reading the read head of data from disk and write the writing head of data to disk. Read head is made up of a MR read head usually, such as, have current-perpendicular-to-the-plane type (CPP), electric current at the read head such as plane inner mold (CIP), TMR, GMR or AMR. For ease of understanding, the present invention only describes emphatically CPP-TMR read head. Obviously, those skilled in the art are after reading this specification, it is understood that the present invention is being applied to the situation of other read heads.
Fig. 3 a illustrates a magnetic head 200, and it comprises substrate body 201, relative ABS202 and bottom surface (not shown) and relative front 203 and tail limit (not shown). This ABS202 is machined to suitable flight height. Front 203 is provided with MR read head 210 and writing head 220, specifically, as shown in Figure 3 b, this MR read head 210 comprises and is formed in the first screen layer 211 on a substrate (not shown), the 2nd screen layer 212, and layer presss from both sides the MR element 230 between this first, second screen layer 211,212.Wherein, being provided with one in the both sides of MR element 230 to hard magnetosphere 240, the same layer of this hard magnetosphere 240 is sandwiched between this first, second screen layer 211,212.
Apply to have first magnetic field of first party to 291 to MR read head 210, this first party is perpendicular to ABS202 to 291, namely the first magnetic field with ABS202 in 90 �� through ABS202, this first party is called as " transverse direction " to 291. Under the design of the present invention, can applying to have to MR read head 201 the 2nd magnetic field of second direction 292, to test performance and the characteristic of MR read head 210, this second direction 292 is perpendicular to first, second screen layer 211,212. Specificly, in the example of reality, this second direction 292 can be worn to the 2nd screen layer 212 (being hereafter called visually in " outflow direction ") from the first screen layer 211, or wears to the first screen layer 211 (being hereafter called visually " inflow direction ") from the 2nd screen layer 212. This outflow direction and inflow direction are all in 90 �� with first, second screen layer 211,212. As a kind of manifestation, it is negative value that this kind flows out the magnetic field in direction, and the magnetic field of inflow direction is for be just worth.
Applying first party is respectively show to the sectional view of 291 and the MR read head 210 in the magnetic field of second direction 292 to 291 and second direction 292, Fig. 4 a and Fig. 4 b for understanding first party better. Wherein, Fig. 4 a illustrates second direction 292, Fig. 4 b in inflow direction and illustrates the second direction 292 flowing out direction.
Fig. 5 is the schema that the present invention tests an embodiment of the method for magnetic head resistance to elevated temperatures. The method comprises the following steps:
Step (501), applies the first magnetic field of multiple varying strength with first party to 291 to magnetic head 210, and measures the first output parameter curve C 1;
Step (502), repeats to apply with second direction 292 the 2nd magnetic field of varying strength, applies the first magnetic field of change simultaneously with first party to 291, and measure multiple 2nd output parameter curve C 2��Cn; And
Step (503), judges whether there is, in the first output parameter curve C 1 and the 2nd output parameter curve C 2��Cn, the change exceeding permissible value, thus filters out bad magnetic head.
If the change being presented on curve is outside the scope of permissible value, then this tested magnetic head is judged as the bad magnetic head manifesting not good performance (as produced a large amount of noises) in high temperature environments, thus is rejected; Otherwise it is salable product. As one performance, huge change presents the maximum transition that a transition rate is greater than 8%. In other words, if the transition rate of this maximum transition is greater than 8%, then this tested magnetic head is defective products. Intuitively, this defective products can present violent shake on output curve.
Specificly, using output voltage as output parameter in the present invention, certainly under the design of the present invention, other output parameters, as resistance, signal to noise ratio etc. also can use.
As for for the testing time of a magnetic head and the selection of magneticstrength, then depend on actual demand and determine. Contriver's discovery applies the identical multiple positive flux field of absolute value respectively and multiple negative fluxfield is tested, and test result and test precision are all better. Detailed description is hereafter describing.
Fig. 6 a��6i illustrates the present invention based on the embodiment shown in Fig. 5, tests a preferred embodiment of the method for magnetic head resistance to elevated temperatures. In the present embodiment, magnetic head is carried out the magnetization of nine times and measures the operation of output voltage. The scope of the intensity in the first magnetic field and the 2nd magnetic field is-800Oe��800Oe.Specifically, the first magnetic field applying within the scope of-800Oe��800Oe to 291 to magnetic head 210 to be perpendicular to the first party of ABS202, the 2nd magnetic field in second direction 292 is then 0Oe simultaneously, and then measures the first output voltage curve C 1. Specificly, this operation is recycled three times, therefore has three curves in each graphic representation in test each time.
Equally, for the 2nd output voltage curve, the sampling in the first magnetic field is between-800Oe��800Oe. The sampling in the 2nd magnetic field is then 0Oe, 50Oe, 100Oe, 150Oe, 200Oe ,-50Oe ,-100Oe ,-150Oe and-200Oe. Specifically, multiple the first magnetic field between-800Oe��800Oe is applied to 291 to magnetic head 210 to be perpendicular to the first party of ABS202, simultaneously to be perpendicular to first, second screen layer 211,212 and to wear, from the 2nd screen layer 212, the 2nd magnetic field that the second direction 292 (i.e. inflow direction) to the first screen layer 211 applies 50Oe, measure the 2nd output voltage curve C 2 with this. And when the magnetic field of negative value must be applied, then wear the second direction 292 (namely flowing out direction) to the 2nd screen layer 212 apply corresponding magnetic field to be perpendicular to first, second screen layer 211,212 and to cover layer 211 from first. Repeat this kind of magnetization operation and measurement until the data in the 2nd above-mentioned magnetic field are all tested, finally measure output voltage parameter curve C 3��C9.
In above-mentioned graphic representation, transverse axis represents magneticstrength, represents the magneticstrength (unit is Oe) in the first magnetic field specificly, and the longitudinal axis represents the output voltage (unit be �� V) of tested magnetic head after magnetization.
In graphic representation C1��C9 visible, C6, C7, C8, C9 all occur bigger transition, the intensity in its 2nd magnetic field is-50Oe ,-100Oe ,-150Oe and-200Oe respectively. Wherein, C6 occurs maximum transition, learn that its transition rate is 14.8% through calculating, be far longer than permissible value 8%. Therefore, can judge that this tested magnetic head is as bad magnetic head, can produce a large amount of noises when this bad magnetic head uses in high temperature environments according to this.
Fig. 7 a��7i illustrates the test curve adopting aforesaid method to be tested by another magnetic head. Therefrom visible, in the middle of the output voltage curve of C7, C8, present bigger transition, the intensity in its 2nd magnetic field is-100Oe and-150Oe respectively. Specifically, C8 occurs maximum transition, learn that its transition rate is 15.7% through calculating. Equally, therefore, if a large amount of noises can be produced when this tested magnetic head uses in high temperature environments, it is defective products.
Contriver adopts the testing method of the present invention that the sampling of a large amount of magnetic head was carried out test, it has been found that the test precision of the testing method of the present invention is good, up to 75%. In the present invention, two typical embodiments are only enumerated.
Compared with prior art, the present invention applies the 2nd magnetic field to magnetic head to be perpendicular to the second direction of screen layer, and measures the output of magnetic head according to this, and the operation repeatedly repeating this kind of magnetization and measuring, finally filters out bad magnetic head in multiple output curve. The present invention when not heated by magnetic head, at room temperature then can detect out the bad magnetic head of a large amount of noise of potential generation in high temperature environments. Therefore comparing prior art, this kind of testing method is improved. Again and, the present invention can detect out the bad magnetic head that the general magnetized traditional method of employing cannot detect completely, and accuracy of detection is reliable.
It is noted that the first party of above-described embodiment to (that is laterally) for wearing the direction into ABS, but be not limited to this.Under the design of the present invention, first party is to also passing from ABS.
Fig. 8 illustrates the embodiment that the present invention tests the device of magnetic head resistance to elevated temperatures. As shown in the figure, this device 800 comprises the first magnetic field applying unit 801, its for first party to the first magnetic field applying multiple varying strength to magnetic head; First measuring unit 802, it is for measuring the first output parameter curve according to the first magnetic field; 2nd magnetic field applying unit 803, it is for repeating to apply to magnetic head the 2nd magnetic field of varying strength with second direction, simultaneously with first party to the first magnetic field applying change; 2nd measuring unit 804, it is for measuring multiple 2nd output parameter curve; And judging unit 805, whether it exists, in the first output parameter curve and the 2nd output parameter curve, the change exceeding permissible value for judging, thus filters out bad magnetic head. Wherein, this first party is to the air bearing face being perpendicular to magnetic head, and second direction is perpendicular to the screen layer of magnetic head.
Specifically, this device 800 comprises the 3rd magnetic field applicator (not shown) further, and it is for applying the 3rd magnetic field with third direction to magnetic head, and this third direction is parallel to screen layer and becomes 0 �� of angle with air bearing face.
The device 800 of the testing method that this execution is above-mentioned, it is possible to high precision filters out the bad magnetic head using in high temperature environments and poorer performance occur. This device 800 can obtain all advantages described in above-mentioned measuring method.
Under the design of the present invention, in the middle of the multiple quasi static test (Quasi-StaticTest, QST) of magnetic head, apply the 2nd magnetic field to be perpendicular to the second direction of screen layer to magnetic head. Fig. 9 illustrates the schema that the present invention tests an embodiment of magnetic head performance, and it at least comprises the following steps:
Step (901), applies the 2nd magnetic field to be perpendicular to the second direction of the screen layer of magnetic head to magnetic head, and surveys the output parameter of magnetic head; And
Step (902), repeats to apply the 2nd magnetic field of varying strength and measures repeatedly output parameter.
If desired, in QST, it is possible to the first party being perpendicular to ABS applies the first magnetic field to magnetic head, or to be parallel to screen layer and to become with ABS the third direction of 0 �� to apply the 3rd magnetic field.
In particular, as implied above, according to reality test, this first party is worn into ABS and situation about passing from ABS to comprising, and second direction comprises and flows out direction and inflow direction. Specifically, this first, second output parameter can be represented by output voltage, resistance or signal to noise ratio.
Correspondingly, Figure 10 illustrates the embodiment that the present invention tests the device of magnetic head performance. As shown in the figure, this device 1000 comprises the 2nd magnetic field applying unit 1002, and it repeats to apply the 2nd magnetic field of varying strength for the second direction to be perpendicular to screen layer to magnetic head; And measuring unit 1003, it for measuring the output parameter of magnetic head according to the 2nd magnetic field, thus tests the performance of magnetic head.
Specifically, this device 1000 comprises the first magnetic field applying unit (not shown) further, and it is for applying the first magnetic field to be perpendicular to the first party of ABS to magnetic head.
Can selection of land, this device 1000 comprises the 3rd magnetic field applying unit (not shown) further, its for be parallel to screen layer and become with ABS the third direction of 0 �� to magnetic head apply the 3rd magnetic field.
The device 1000 of the testing method that this execution is above-mentioned, it is possible to high precision filters out the bad magnetic head using in high temperature environments and poorer performance occur. If desired, this device 1000 can comprise the functional unit corresponding with above-mentioned testing method, omits at this and describes.
The above disclosed better embodiment being only the present invention, can not limit the interest field of the present invention certainly with this, and the equivalent variations therefore done according to the present patent application patent scope, still belongs to the scope that the present invention is contained.
Claims (30)
1. testing a method for MR read head resistance to elevated temperatures, MR read head comprises air bearing face and two screen layers, and described method comprises:
With first party to the first magnetic field applying multiple varying strength to described MR read head, and measure the first output parameter curve;
Repeat to apply with second direction the 2nd magnetic field of varying strength, simultaneously with first party to the first magnetic field applying change, and measure multiple 2nd output parameter curve; And
Judge whether the change of described first output parameter curve and described 2nd output parameter curve presents the maximum transition being greater than predetermined transition rate, thus filter out bad MR read head;
It is characterized in that: described first party is to the air bearing face being perpendicular to described MR read head, and described second direction is perpendicular to the screen layer of described MR read head.
2. the method for claim 1, it is characterised in that: also comprising and apply the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described screen layer and becomes 0 �� of angle with described air bearing face.
3. the method for claim 1, it is characterised in that: described first party passes to wearing into described air bearing face or from described air bearing face.
4. the method for claim 1, it is characterised in that: described screen layer comprises the first screen layer and the 2nd screen layer, and described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
5. the method for claim 1, it is characterised in that: the scope of the intensity in described first magnetic field and the intensity in described 2nd magnetic field is-800Oe��800Oe.
6. the method for claim 1, it is characterised in that: the intensity in described 2nd magnetic field comprises multiple numerical value pair with same absolute.
7. the method for claim 1, it is characterised in that: described first output parameter curve and described 2nd output parameter curve are represented by output voltage.
8. the method for claim 1, it is characterised in that: described first output parameter curve and described 2nd output parameter curve are represented by signal to noise ratio.
9. the method for claim 1, it is characterised in that: described predetermined transition rate is 8%.
10. testing a method for MR read head performance, MR read head comprises air bearing face and two screen layers, it is characterised in that, described method comprises:
Apply the 2nd magnetic field to be perpendicular to the second direction of described screen layer to described MR read head, and measure the output parameter of described MR read head; And
Repeat to apply the 2nd magnetic field of varying strength, and measure repeatedly output parameter;
Described method also comprises and applies the first magnetic field with first party to described MR read head, and described first party is to the air bearing face being perpendicular to described MR read head.
11. methods as claimed in claim 10, it is characterised in that: also comprising and apply the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described screen layer and becomes 0 �� of angle with described air bearing face.
12. methods as claimed in claim 10, it is characterised in that: described first party passes to wearing into described air bearing face or from described air bearing face.
13. methods as claimed in claim 10, it is characterized in that: described screen layer comprises the first screen layer and the 2nd screen layer, described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
14. methods as claimed in claim 10, it is characterised in that: described output parameter is represented by output voltage.
15. methods as claimed in claim 10, it is characterised in that: described output parameter is represented by signal to noise ratio.
Testing the device of MR read head resistance to elevated temperatures for 16. 1 kinds, MR read head comprises air bearing face and two screen layers, and described device comprises:
First magnetic field applying unit, for first party to the first magnetic field applying multiple varying strength to described MR read head;
First measuring unit, for measuring the first output parameter curve according to described first magnetic field;
2nd magnetic field applying unit, for repeating to apply to described MR read head the 2nd magnetic field of varying strength with second direction, simultaneously with first party to the first magnetic field applying change;
2nd measuring unit, for measuring multiple 2nd output parameter curve; And
Whether judging unit, present, for judging the change of described first output parameter curve and described 2nd output parameter curve, the maximum transition being greater than predetermined transition rate, thus filter out bad MR read head;
It is characterized in that: described first party is to the air bearing face being perpendicular to described MR read head, and described second direction is perpendicular to the screen layer of described MR read head.
17. devices as claimed in claim 16, it is characterised in that: also comprising the 3rd magnetic field applying unit, for applying the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described screen layer and becomes 0 �� of angle with described air bearing face.
18. devices as claimed in claim 16, it is characterised in that: described first party passes to wearing into described air bearing face or from described air bearing face.
19. devices as claimed in claim 16, it is characterized in that: described screen layer comprises the first screen layer and the 2nd screen layer, described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
20. devices as claimed in claim 16, it is characterised in that: the scope of the intensity in described first magnetic field and the intensity in described 2nd magnetic field is-800Oe��800Oe.
21. devices as claimed in claim 16, it is characterised in that: the intensity in described 2nd magnetic field comprises multiple numerical value pair with same absolute.
22. devices as claimed in claim 16, it is characterised in that: described first output parameter curve and described 2nd output parameter curve are represented by output voltage.
23. devices as claimed in claim 16, it is characterised in that: described first output parameter curve and described 2nd output parameter curve are represented by signal to noise ratio.
24. devices as claimed in claim 16, it is characterised in that: described predetermined transition rate is 8%.
Testing the device of MR read head performance for 25. 1 kinds, MR read head comprises air bearing face and two screen layers, it is characterised in that, described device comprises:
2nd magnetic field applying unit, repeats to apply the 2nd magnetic field of varying strength for the second direction to be perpendicular to described screen layer to described MR read head; And
Measuring unit, for measuring the output parameter of described MR read head according to described 2nd magnetic field;
Described measuring apparatus also comprises the first magnetic field applying unit, and for applying the first magnetic field with first party to described MR read head, described first party is to being perpendicular to described air bearing face.
26. devices as claimed in claim 25, it is characterised in that: also comprising the 3rd magnetic field applying unit, for applying the 3rd magnetic field with third direction to described MR read head, described third direction is parallel to described screen layer and becomes 0 �� of angle with described air bearing face.
27. devices as claimed in claim 25, it is characterised in that: described first party passes to wearing into described air bearing face or from described air bearing face.
28. devices as claimed in claim 25, it is characterized in that: described screen layer comprises the first screen layer and the 2nd screen layer, described second direction points to described 2nd screen layer from described first screen layer, or points to described first screen layer from described 2nd screen layer.
29. devices as claimed in claim 25, it is characterised in that: described output parameter is represented by output voltage.
30. devices as claimed in claim 25, it is characterised in that: described output parameter is represented by signal to noise ratio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110109622.4A CN102760449B (en) | 2011-04-29 | 2011-04-29 | The method of test magnetic head resistance to elevated temperatures and device thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110109622.4A CN102760449B (en) | 2011-04-29 | 2011-04-29 | The method of test magnetic head resistance to elevated temperatures and device thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102760449A CN102760449A (en) | 2012-10-31 |
| CN102760449B true CN102760449B (en) | 2016-06-08 |
Family
ID=47054888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201110109622.4A Active CN102760449B (en) | 2011-04-29 | 2011-04-29 | The method of test magnetic head resistance to elevated temperatures and device thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102760449B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104143343B (en) * | 2013-05-09 | 2018-08-10 | 新科实业有限公司 | Head test method and test device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7683610B2 (en) * | 2008-03-03 | 2010-03-23 | Tdk Corporation | Method for inspecting magnetic characteristics of a plurality of thin magnetic heads by means of local application of magnetic field |
| CN101807406A (en) * | 2009-01-21 | 2010-08-18 | Tdk株式会社 | Examination method for cpp-type magnetoresistance effect element having two free layers |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100338441B1 (en) * | 1998-10-21 | 2002-05-27 | 포만 제프리 엘 | High coercivity multifilm hard magnetic layer for magnetically stabilizing a spin valve sensor |
| US8080992B2 (en) * | 2007-11-15 | 2011-12-20 | Infinitum Solutions, Inc. | Write head tester using inductance |
| US9548083B2 (en) * | 2007-12-10 | 2017-01-17 | Infinitum Solutions, Inc. | Read sensor testing using thermal magnetic fluctuation noise spectra |
-
2011
- 2011-04-29 CN CN201110109622.4A patent/CN102760449B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7683610B2 (en) * | 2008-03-03 | 2010-03-23 | Tdk Corporation | Method for inspecting magnetic characteristics of a plurality of thin magnetic heads by means of local application of magnetic field |
| CN101807406A (en) * | 2009-01-21 | 2010-08-18 | Tdk株式会社 | Examination method for cpp-type magnetoresistance effect element having two free layers |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102760449A (en) | 2012-10-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5514953A (en) | Wafer level test structure for detecting multiple domains and magnetic instability in a permanent magnet stabilized MR head | |
| US8664950B2 (en) | Method for measuring longitudinal bias magnetic field in a tunnel magnetoresistive sensor | |
| US8594967B2 (en) | Method for measuring the temperature rise induced by bias current/bias voltage in a magnetic tunnel junction | |
| US7633694B2 (en) | Method and apparatus for quantifying stress and damage in magnetic heads | |
| US8018226B2 (en) | Methods for detecting damage to magnetoresistive sensors | |
| US9714985B2 (en) | Calibration assembly for aide in detection of analytes with electromagnetic read-write heads | |
| US10600434B2 (en) | System for detecting damaged magnetoresistive sensor | |
| US10656232B2 (en) | Calibrating read sensors of electromagnetic read-write heads | |
| US20130164777A1 (en) | Magnetic Flow Cytometry for Individual Cell Detection | |
| CN102760449B (en) | The method of test magnetic head resistance to elevated temperatures and device thereof | |
| CN102760448B (en) | The method of test magnetic head resistance to elevated temperatures and device thereof | |
| US6433540B1 (en) | Method and apparatus for testing composite type magnetic head having a magnetoresistive element and an inductive element | |
| US6340885B1 (en) | Method and apparatus for testing composite type magnetic head | |
| US6255814B1 (en) | Method and apparatus for measuring bias magnetic field for controlling magnetic domain of magnetoresistive effect element | |
| US9899046B2 (en) | Method of testing anti-high temperature performance of a magnetic head and apparatus thereof | |
| US9121888B2 (en) | Method of testing anti-high temperature performance of a magnetic head and apparatus thereof | |
| CN205388456U (en) | Displacement sensor and displacement sensing measurement system | |
| JP2002133621A (en) | Method and device for inspecting magnetic head with magnetoresistance effect element | |
| CN104143343B (en) | Head test method and test device | |
| US20060066299A1 (en) | Reverse magnetic reset to screen for weakly pinned heads | |
| CN103093763B (en) | The measuring method and its measurement apparatus of magnetic head | |
| US8493683B2 (en) | Measuring method of a magnetic head and measuring apparatus thereof | |
| JP2006302414A (en) | Method and device for inspecting composite magnetic head | |
| JP2009224002A (en) | Method of evaluating magnetic head, magnetic disk device and manufacturing method thereof | |
| JP2002063707A (en) | Method and device for inspecting thin film magnetic head |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |