CA1101120A - Magneto-resistive reading head - Google Patents
Magneto-resistive reading headInfo
- Publication number
- CA1101120A CA1101120A CA288,728A CA288728A CA1101120A CA 1101120 A CA1101120 A CA 1101120A CA 288728 A CA288728 A CA 288728A CA 1101120 A CA1101120 A CA 1101120A
- Authority
- CA
- Canada
- Prior art keywords
- magneto
- magnetization
- magnetic
- easy axis
- resistive
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
- G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
- G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
Abstract
ABSTRACT
A magnetic reading head having a magneto-resistive element of the non-magnetically biased type, in which the current is forced to flow through the element at an angle with the easy axis of magnetization. For adjusting the dynamic range of the element (for example, in behalf of the application of different types of tape) means are present to subject the element to an auxiliary field the strength of which can be varied and the direction of which is parallel to the easy axis of magnetization.
A magnetic reading head having a magneto-resistive element of the non-magnetically biased type, in which the current is forced to flow through the element at an angle with the easy axis of magnetization. For adjusting the dynamic range of the element (for example, in behalf of the application of different types of tape) means are present to subject the element to an auxiliary field the strength of which can be varied and the direction of which is parallel to the easy axis of magnetization.
Description
~- ` PlrN ~5~l~
~ Zo BKS/YMB/~OPP
"Magneto-resistive reading head".
The inventlon relat~s to a magnetic reading head for detecting information-representing magnetic fields on a magnetic recording medium, comprising a magneto-resisti~e element of metallic ferromagnetic material which is supported on a substrate~ which has an easy axis of magnetization in the plane of the element and which is provided with electrical contacts for enabling it to be connected to a source of Measur-ing current, means which force the measuring current to flow through the element at an angle of at le~t 35 and at most 55 with the easy axis of magnetization, and a magnetic device for subjecting the element to a magnetic auxiliary field which is parallel to the easy axis of magnetization.
A head of the above-men-tioned kind is described in "The Barberpole~ a linear magneto-resistive head" in IEEE Transactions on Magnetics, September 1975~ Vol. MAG 11 No. 5, pp 1215-1217.
This paper describes a head using a strip-shaped element of a ferro-mag~etic metallic material having low . .
anisotropy, for example Ni-~e, which is held with one of its edges in the immediate proximity of, or in contact with, a magnetic recording medium. The fields on the recording medium produce variations in the magnetization of the element when the medium is moved across the head and modulate the resistance thereof ~ia the magneto-resistance effect. Thus, ~len -the recording medium passes the head, the information~representing magnetic fields present on the medium rotate the spin system
~ Zo BKS/YMB/~OPP
"Magneto-resistive reading head".
The inventlon relat~s to a magnetic reading head for detecting information-representing magnetic fields on a magnetic recording medium, comprising a magneto-resisti~e element of metallic ferromagnetic material which is supported on a substrate~ which has an easy axis of magnetization in the plane of the element and which is provided with electrical contacts for enabling it to be connected to a source of Measur-ing current, means which force the measuring current to flow through the element at an angle of at le~t 35 and at most 55 with the easy axis of magnetization, and a magnetic device for subjecting the element to a magnetic auxiliary field which is parallel to the easy axis of magnetization.
A head of the above-men-tioned kind is described in "The Barberpole~ a linear magneto-resistive head" in IEEE Transactions on Magnetics, September 1975~ Vol. MAG 11 No. 5, pp 1215-1217.
This paper describes a head using a strip-shaped element of a ferro-mag~etic metallic material having low . .
anisotropy, for example Ni-~e, which is held with one of its edges in the immediate proximity of, or in contact with, a magnetic recording medium. The fields on the recording medium produce variations in the magnetization of the element when the medium is moved across the head and modulate the resistance thereof ~ia the magneto-resistance effect. Thus, ~len -the recording medium passes the head, the information~representing magnetic fields present on the medium rotate the spin system
-2~
.
..
PIIN S5~4 7-~) 197~
of the magneto-resistive element to cause a variation in the electrical resistance pf the element. When a detection circuit is conn.ected to the element then an output signal from this circuit can be a function of the~lnformation stored in the recording medium.
Since the variati.on in the resistance Or a magneto-resist-ive element under the influence of an external rnagnetlc field is quadratic, it is usual in reproducing analogically recorded signals to optimize the operation of the head by linearizat-ion of the resistance-magnetic field characteristic.
For this purpose, -the magnetization direction of the element in the presence of a signal field of zero s-trength should be .caused to make an angle of approximately 45 with the direction of current flow through the element~
. With the magneto-resistive reading head described . in the paper this is achieved by melting the easy axis of magnetization l.ie parallel to the largest dimension o~ the element and providing bias means which force the current to flow through the element at an angle of approximately 45 with th.e longitudinal direction.
The head of the paper furtherrnore comprises a magnetic device for producing a magnetic auxiliary field in a . direction parallel to the easy axis of magnetization of the element. The use of the auxiliary field ensures that one of the two opposite directions along which the magnetization vector may orient itself is favoured more than the other direction so that reversal froln one direction to the other9 which woùld result in a vari.ation of the resistance of the element~ i5 prevented.
: ~3-PlIN ~55l( , 7-~J-197'7 2~3 In magneto-resistive heads of the above-described kind~ the output signal V may be written as V = f (Cy , h, Ho), wherein ~ is the angle between the magnetization and the current direction with a signal field of zero strength, h is the s:ignal field strength of the recording medium, and Ho is a character~
istic quantity for a given magneto-resistive element which may be writtén as H = (d x 4 ~rM ) + Hk, wherein d is the thickness of the magneto-resistive element, w is the height, Ms is the saturation magnetization, and ~ is the anisotropy field.
With a given average value of h it is usual to adjust the angle ~ to provide a minimum distorsion of the output signal. (As already noted, ~ usually has-a value in the proximity of 4~ ). Once ~ has been adjusted, for example, by arranging a pa-ttern of equipotential strips or of slots which force the current to flow at a given ang~e any chan~e of the angle is no longer possible. The dynamic range of h, that is the maximum amplitude of h for a per-missible degree of distorsion, then follows from the character-` istic quantity Eo which is determined by the geometry and the physical properties of the selected element. A disadvantage of this arrangement is that the dynamic range is fixed in construction of the head and it cannot be changed subsequently for example~ to adapt the head to the use of di~ferent recording materials or according to the magnitude of the a~erage signal which is required to be read out.
It is the object of the invention to provlde a .
PHN 85~4 11~311ZO
magnetic reading head of the kind mentioned in the preamble in which the dyna~c range can be adJusted according to the signal required to be read out.
For tha-t purpose, the ~eading head according to the invention is characterized in that, for adjusting the dynami.c range of the element, rneans are present to vary the strength of the auxiliary f:ield between 0.1 Ho and 5 Ho wherein Ho = (d x 4 Ms) ~ ~ , wherein d is the thickness of themagnetoresistive eleme~, w is the height, Ms is the sat~ration magnetization, and ~ is the anisotropy field.
~he invention is based on the fact that by varying the strength of the auxiliary field theslope of the resistance-signal field characteristic of linearized magneto-, . .
resistive elements of the present kind, that is to say 15 . linearized by non-magnetic means, varies with the operating y point remaining the same. This in oontrast with the behaviour of magneto-resistive elements the characteristic.
of which is linearized by applying a magnetic field at right angles to the easy axis of magnetization. In magneto-resistive elements of such a magnetically biased type, the operating point shifts when the strength of the bias field is varied, so distorsion occurs.
'' ~f'~ ' ' Although it is possible in non-magnetically biased ;~ . magneto-resistive heads of the k.ind mentioned in ~e preamble to enforce the d~sired current direction in various manners~
for example, by providing slots in the element which extend at the deslred angle with respect to the longitudinal direction I?~N g554 ~ 20 7-6-~977 and alternately open into the upper and lower side, a dif~erent construction is used -n a preferred embodiment o~ the inven-tion.
According to a di~ferent aspect of the invention there is provided a head in which the easy a~is of magnetization is parallel to the ~argest dimension of the element and in that a number of parallel equipotential strips of electrically conductive material are provided on a major surface of the magneto-resistive element at an angle of at least 35 and at most 55 with the largest dimension between the contacts.
An advantage of this construction is that in applications in which the magneto-resisti~Te element -ls in contact with the recording medium, the improvod operation need not be lost in tlie event of some surface wear of the element which would be likely in a construction having slots. In addition, the magnetic continuity of a magneto-resistive element is not interrupted when equipotential strips are provided on it. In a construction having slots on the contrary the magnetic continuity may possibly become damaged when surface wear occurs.
The invention will now be described in greater detail, by way of examplej with re~erence to the accompanying drawings, but is not restricted to this embodiment.
In the drawings:
.. .
Fig. 1 is a simplified perspective view of a magnetic reading head according to the invelltion with the associated circuits in block form.
Fig. 2 shows the individual components of Fig.
1 on an enlarged sca]e.
--6_
.
..
PIIN S5~4 7-~) 197~
of the magneto-resistive element to cause a variation in the electrical resistance pf the element. When a detection circuit is conn.ected to the element then an output signal from this circuit can be a function of the~lnformation stored in the recording medium.
Since the variati.on in the resistance Or a magneto-resist-ive element under the influence of an external rnagnetlc field is quadratic, it is usual in reproducing analogically recorded signals to optimize the operation of the head by linearizat-ion of the resistance-magnetic field characteristic.
For this purpose, -the magnetization direction of the element in the presence of a signal field of zero s-trength should be .caused to make an angle of approximately 45 with the direction of current flow through the element~
. With the magneto-resistive reading head described . in the paper this is achieved by melting the easy axis of magnetization l.ie parallel to the largest dimension o~ the element and providing bias means which force the current to flow through the element at an angle of approximately 45 with th.e longitudinal direction.
The head of the paper furtherrnore comprises a magnetic device for producing a magnetic auxiliary field in a . direction parallel to the easy axis of magnetization of the element. The use of the auxiliary field ensures that one of the two opposite directions along which the magnetization vector may orient itself is favoured more than the other direction so that reversal froln one direction to the other9 which woùld result in a vari.ation of the resistance of the element~ i5 prevented.
: ~3-PlIN ~55l( , 7-~J-197'7 2~3 In magneto-resistive heads of the above-described kind~ the output signal V may be written as V = f (Cy , h, Ho), wherein ~ is the angle between the magnetization and the current direction with a signal field of zero strength, h is the s:ignal field strength of the recording medium, and Ho is a character~
istic quantity for a given magneto-resistive element which may be writtén as H = (d x 4 ~rM ) + Hk, wherein d is the thickness of the magneto-resistive element, w is the height, Ms is the saturation magnetization, and ~ is the anisotropy field.
With a given average value of h it is usual to adjust the angle ~ to provide a minimum distorsion of the output signal. (As already noted, ~ usually has-a value in the proximity of 4~ ). Once ~ has been adjusted, for example, by arranging a pa-ttern of equipotential strips or of slots which force the current to flow at a given ang~e any chan~e of the angle is no longer possible. The dynamic range of h, that is the maximum amplitude of h for a per-missible degree of distorsion, then follows from the character-` istic quantity Eo which is determined by the geometry and the physical properties of the selected element. A disadvantage of this arrangement is that the dynamic range is fixed in construction of the head and it cannot be changed subsequently for example~ to adapt the head to the use of di~ferent recording materials or according to the magnitude of the a~erage signal which is required to be read out.
It is the object of the invention to provlde a .
PHN 85~4 11~311ZO
magnetic reading head of the kind mentioned in the preamble in which the dyna~c range can be adJusted according to the signal required to be read out.
For tha-t purpose, the ~eading head according to the invention is characterized in that, for adjusting the dynami.c range of the element, rneans are present to vary the strength of the auxiliary f:ield between 0.1 Ho and 5 Ho wherein Ho = (d x 4 Ms) ~ ~ , wherein d is the thickness of themagnetoresistive eleme~, w is the height, Ms is the sat~ration magnetization, and ~ is the anisotropy field.
~he invention is based on the fact that by varying the strength of the auxiliary field theslope of the resistance-signal field characteristic of linearized magneto-, . .
resistive elements of the present kind, that is to say 15 . linearized by non-magnetic means, varies with the operating y point remaining the same. This in oontrast with the behaviour of magneto-resistive elements the characteristic.
of which is linearized by applying a magnetic field at right angles to the easy axis of magnetization. In magneto-resistive elements of such a magnetically biased type, the operating point shifts when the strength of the bias field is varied, so distorsion occurs.
'' ~f'~ ' ' Although it is possible in non-magnetically biased ;~ . magneto-resistive heads of the k.ind mentioned in ~e preamble to enforce the d~sired current direction in various manners~
for example, by providing slots in the element which extend at the deslred angle with respect to the longitudinal direction I?~N g554 ~ 20 7-6-~977 and alternately open into the upper and lower side, a dif~erent construction is used -n a preferred embodiment o~ the inven-tion.
According to a di~ferent aspect of the invention there is provided a head in which the easy a~is of magnetization is parallel to the ~argest dimension of the element and in that a number of parallel equipotential strips of electrically conductive material are provided on a major surface of the magneto-resistive element at an angle of at least 35 and at most 55 with the largest dimension between the contacts.
An advantage of this construction is that in applications in which the magneto-resisti~Te element -ls in contact with the recording medium, the improvod operation need not be lost in tlie event of some surface wear of the element which would be likely in a construction having slots. In addition, the magnetic continuity of a magneto-resistive element is not interrupted when equipotential strips are provided on it. In a construction having slots on the contrary the magnetic continuity may possibly become damaged when surface wear occurs.
The invention will now be described in greater detail, by way of examplej with re~erence to the accompanying drawings, but is not restricted to this embodiment.
In the drawings:
.. .
Fig. 1 is a simplified perspective view of a magnetic reading head according to the invelltion with the associated circuits in block form.
Fig. 2 shows the individual components of Fig.
1 on an enlarged sca]e.
--6_
3 ~I-IN 855/1 _ 7-6-1977 1~ 0 I~`ig. 3 is a ~raph showin~ the resistance variation ~ R/ ~ RM~X of the magneto-resistive element 3 of the head shown in ~ig. 1 as a function of a transversal external field h~ at various values of a longitudinal field hy.
F:ig, 1 shows a magneto-resistive head 1 which is depicted in use for reading the information content of a magnetic recording medium 2. The head 1 comprises a magneto-resistive element 3 which is connected to an external reading circuit 6 via electrically conductive contacts 4 and 5. The . .
element 37 and the contacts 4 and 5 are formed on a substrate 7, which may be glass, by means of thin-Pilm techniques. For ; supplying a measuring current, a current source 8 is connected to the ContaGt 4 and 5. Fig. 2, in which the same re-Perence numerals as those in Fig. 1 are used for the same components, shows the individual components of the head on a larger scale.
In this embodiment to the element 3 was a thin layer of an Ni-Fe alloy having a thickness d of approximately 0.1 micron, a le3~gth 1 of 100 microns and a height w o-P 10 microns. The ., .
contacts 4 and 5 are formed by vapour-deposited gold strips.
A number of thin gold strips 9, thickness 1 micron, width 2 microns, are provided on the element 3 at a mutual distance of 2.5 microns and at an angle olP 45 The gold has a 5 times lower resis*ivity than the Ni-Fe alloy used~ and the~-thickness of the gold strips is approximately 10 times as large as the thickness d Or the magneto-resistive elernent material. Therefore the gold strips c03lduct 50 times better and serve as "equipotential strips" which force the current in the Ni-Fe path between them to flow at an angle of approximate]v 45 .
PHN ~r~5ll ` 7-~-1977 ll~llZO
with the longitudirlal d-irection. When t;he head is brought in flux coupling with an information-containillg magnetic field, the resistance of eacll of the ~i-Fe paths situated between the equipotential strips 9 will decrease or increase in accordance with the fact whether the direction of magncti~ation under the influence of the field coincides rnore or less with the direction of current. In this manner, magnetic recordings can be reproduced with 10w distortion by means of a non-magnetically biased magneto~resistive head.
A longitudinal auxiliary field 3-I~ is generated by means of a magnet core 10. The strength of aid auxiliary field can be varied between 0.1 Ho and 5 Ho by varying a current through a coil 11 which is connec-ted to a variable current source 12, IIo being a characteristic quantity, as ; 15 defined above, for the dimensions and material of the element in question. Said field strength may be such that it is unlittely to damage the stored information on the medium 2.
It is alternatively possible to use a permanent magnet which is magnetized parallel to the longitudinal direction of the magneto~resistive element and which is supported at a variable distance from the element, The use of a permanent magnet i~ illustrated diagrammatically in Fig. 3 wllichs~ows a substrate 13 on which a non-magnetically biased magneto-resistive element 14 is pro~7ided and a magnet 16 which can be -~ 2~ moved by means of a screw 15. In or~er to illustrate the effects of the variation of the au~iliary field, Fig. 4 j shows the variation ~ R/ ~ Rma~ of the resistance of the elemellt 3 under the iDfluence of` a sienal field Hz .
''. . .
~ ~'MN 8554 ~ ZO 7-~-1977 with various strengths of an au~iliary ~ield h~, in the +y direction. It is to be noted that both the signal field h and the auxiliary field hy are standardized~ that is hz = ~z/Ho and hy = Hy/H , where Mz and My are the actual signal -~leld stren~th and the actual longitudinal field strength, respectively. The characteristic quantity Ho which depends inter alia on the ratio height/thickness w/d in practive proves to be usually between ten and a hundred Oersteds.
,. ' ~ .
. :
.~ Q ~ `
' ' ' ,' . . ' .
`' : , '` ~
;
. ' ' ' .
. . . .
_9_ O
F:ig, 1 shows a magneto-resistive head 1 which is depicted in use for reading the information content of a magnetic recording medium 2. The head 1 comprises a magneto-resistive element 3 which is connected to an external reading circuit 6 via electrically conductive contacts 4 and 5. The . .
element 37 and the contacts 4 and 5 are formed on a substrate 7, which may be glass, by means of thin-Pilm techniques. For ; supplying a measuring current, a current source 8 is connected to the ContaGt 4 and 5. Fig. 2, in which the same re-Perence numerals as those in Fig. 1 are used for the same components, shows the individual components of the head on a larger scale.
In this embodiment to the element 3 was a thin layer of an Ni-Fe alloy having a thickness d of approximately 0.1 micron, a le3~gth 1 of 100 microns and a height w o-P 10 microns. The ., .
contacts 4 and 5 are formed by vapour-deposited gold strips.
A number of thin gold strips 9, thickness 1 micron, width 2 microns, are provided on the element 3 at a mutual distance of 2.5 microns and at an angle olP 45 The gold has a 5 times lower resis*ivity than the Ni-Fe alloy used~ and the~-thickness of the gold strips is approximately 10 times as large as the thickness d Or the magneto-resistive elernent material. Therefore the gold strips c03lduct 50 times better and serve as "equipotential strips" which force the current in the Ni-Fe path between them to flow at an angle of approximate]v 45 .
PHN ~r~5ll ` 7-~-1977 ll~llZO
with the longitudirlal d-irection. When t;he head is brought in flux coupling with an information-containillg magnetic field, the resistance of eacll of the ~i-Fe paths situated between the equipotential strips 9 will decrease or increase in accordance with the fact whether the direction of magncti~ation under the influence of the field coincides rnore or less with the direction of current. In this manner, magnetic recordings can be reproduced with 10w distortion by means of a non-magnetically biased magneto~resistive head.
A longitudinal auxiliary field 3-I~ is generated by means of a magnet core 10. The strength of aid auxiliary field can be varied between 0.1 Ho and 5 Ho by varying a current through a coil 11 which is connec-ted to a variable current source 12, IIo being a characteristic quantity, as ; 15 defined above, for the dimensions and material of the element in question. Said field strength may be such that it is unlittely to damage the stored information on the medium 2.
It is alternatively possible to use a permanent magnet which is magnetized parallel to the longitudinal direction of the magneto~resistive element and which is supported at a variable distance from the element, The use of a permanent magnet i~ illustrated diagrammatically in Fig. 3 wllichs~ows a substrate 13 on which a non-magnetically biased magneto-resistive element 14 is pro~7ided and a magnet 16 which can be -~ 2~ moved by means of a screw 15. In or~er to illustrate the effects of the variation of the au~iliary field, Fig. 4 j shows the variation ~ R/ ~ Rma~ of the resistance of the elemellt 3 under the iDfluence of` a sienal field Hz .
''. . .
~ ~'MN 8554 ~ ZO 7-~-1977 with various strengths of an au~iliary ~ield h~, in the +y direction. It is to be noted that both the signal field h and the auxiliary field hy are standardized~ that is hz = ~z/Ho and hy = Hy/H , where Mz and My are the actual signal -~leld stren~th and the actual longitudinal field strength, respectively. The characteristic quantity Ho which depends inter alia on the ratio height/thickness w/d in practive proves to be usually between ten and a hundred Oersteds.
,. ' ~ .
. :
.~ Q ~ `
' ' ' ,' . . ' .
`' : , '` ~
;
. ' ' ' .
. . . .
_9_ O
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. A magnetic reading head for detecting information-representing magnetic fields on a magnetic recording medium, the head comprising a magneto-resistive element of metallic, ferro-magnetic material which is supported on a substrate, which has an easy axis of magnetization in the plane of the element, and which is provided with electrical contacts for enabling it to be connected to a source of measuring current, means which force the measuring current to flow through the element at an angle of at least 35° and at most 55° with the easy axis of magnetization, and a magnetic device to subject the element to a magnetic auxiliary field which is parallel to the easy axis of magnetization, characterized in that, for adjusting the dynamic of the element, means are present to vary the strength of the auxiliary field between 0.1 Ho and 5HO, wherein Ho = (? x 4.pi.Ms) + Hk, wherein d is the thickness of the magneto-resistive element, w is the height, Ms is the saturation magnetization, and Hk is the anisotropy field.
2. A magnetic reading head as claimed in Claim 1, characterized in that the easy axis of magnetization is parallel to the largest dimension of the element and that a number of parallel equipotential strips of electrically conductive material are provided on a major surface of the magneto-resistive element at an angle of at least 35° and at most 55° with the largest dimension between the contacts.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7611521A NL7611521A (en) | 1976-10-19 | 1976-10-19 | MAGNETO RESISTANCE READ HEAD. |
| NL7611521 | 1976-10-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1101120A true CA1101120A (en) | 1981-05-12 |
Family
ID=19827074
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA288,728A Expired CA1101120A (en) | 1976-10-19 | 1977-10-14 | Magneto-resistive reading head |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5352409A (en) |
| CA (1) | CA1101120A (en) |
| DE (1) | DE2744993C2 (en) |
| FR (1) | FR2368777A1 (en) |
| GB (1) | GB1539641A (en) |
| NL (1) | NL7611521A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5559314A (en) * | 1978-10-27 | 1980-05-02 | Sony Corp | Magnetic scale signal detector |
| JPS57109121A (en) * | 1980-12-26 | 1982-07-07 | Sony Corp | Magnetic resistance effect type magnetic head |
| JPS6047223A (en) * | 1983-08-25 | 1985-03-14 | Sony Corp | Magneto-resistance effect type magnetic head |
| GB2191589B (en) * | 1986-06-10 | 1990-06-13 | Nippon Musical Instruments Mfg | Sensor |
| DE19601021B4 (en) * | 1996-01-13 | 2004-11-18 | Dr. Johannes Heidenhain Gmbh | Magnetic position measuring device and method for its operation |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3493694A (en) * | 1966-01-19 | 1970-02-03 | Ampex | Magnetoresistive head |
| GB1272044A (en) * | 1971-02-22 | 1972-04-26 | Mullard Ltd | Improvements in or relating to magnetoresistive readout transducers |
| US3716781A (en) * | 1971-10-26 | 1973-02-13 | Ibm | Magnetoresistive sensing device for detection of magnetic fields having a shape anisotropy field and uniaxial anisotropy field which are perpendicular |
| US3881190A (en) * | 1973-09-20 | 1975-04-29 | Ibm | Shielded magnetoresistive magnetic transducer and method of manufacture thereof |
| US3940797A (en) * | 1973-09-20 | 1976-02-24 | International Business Machines Corporation | Shielded magnetoresistive magnetic transducer |
| NL164410C (en) * | 1974-04-01 | 1980-12-15 | Philips Nv | MAGNETIC RESISTANCE MAGNETIC HEAD. |
| BR9915399A (en) * | 1998-11-16 | 2001-11-27 | Exxonmobil Chem Patents Inc | Soluble complex alcohol ester compounds and compositions |
-
1976
- 1976-10-19 NL NL7611521A patent/NL7611521A/en not_active Application Discontinuation
-
1977
- 1977-10-06 DE DE19772744993 patent/DE2744993C2/en not_active Expired
- 1977-10-14 GB GB4284177A patent/GB1539641A/en not_active Expired
- 1977-10-14 CA CA288,728A patent/CA1101120A/en not_active Expired
- 1977-10-15 JP JP12303077A patent/JPS5352409A/en active Granted
- 1977-10-19 FR FR7731451A patent/FR2368777A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1539641A (en) | 1979-01-31 |
| JPS5713929B2 (en) | 1982-03-20 |
| FR2368777A1 (en) | 1978-05-19 |
| NL7611521A (en) | 1978-04-21 |
| FR2368777B1 (en) | 1984-06-08 |
| JPS5352409A (en) | 1978-05-12 |
| DE2744993C2 (en) | 1986-08-21 |
| DE2744993A1 (en) | 1978-04-20 |
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