US6295225B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic tunnel junction device having an intermediate layer
Assignee: US Philips Corp
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Filing: 2000-03-31
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Granted: 2001-09-25
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Expires: 2020-03-31
Abstract
Abstract A magnetic tunnel junction device has a multi-layer structure including a pair of electrode layers of a ferromagnetic material and a tunnel barrier layer of an insulating material between the electrode layers. In order to realize a low resistance, the multi-layer structure also includes an intermediate layer provided between the barrier layer and one of the electrode layers and including a conductive material having a work function with a value which is at least 25% lower than the value of the work function of the material of the respective electrode layer.
Inventors
- 👤 Wouter Oepts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:07
CPC Classifications
H; H10; H10N; H10N50/00; H10N50/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
84 words
A magnetic tunnel junction device provided with a multi-layer structure comprising a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer.
Claim 2
Dependent Claim
84 words
A magnetic tunnel junction device provided with a multi-layer structure comprising a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer.
Claim 3
Dependent Claim
27 words
The device according to claim 1 , in which the material of the intermediate layer includes a metal of a group including: Cs, Ba, Sr and Y.
Claim 4
Dependent Claim
22 words
The device according to claim 1 , in which the intermediate layer is only provided on one side of the barrier layer.
Claim 5
Dependent Claim
22 words
The device according to claim 2 , in which the intermediate layer is only provided on one side of the barrier layer.
Claim 6
Dependent Claim
100 words
A magnetic field sensor comprising: a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the sensor further comprising an output for a magnetic field signal.
Claim 7
Dependent Claim
100 words
A magnetic field sensor comprising: a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the sensor further comprising an output for a magnetic field signal.
Claim 8
Dependent Claim
41 words
The sensor according to claim 5 , in which: the material of the intermediate layer includes a metal of a group including: Cs, Ba, Sr and Y; and the intermediate layer is only provided on one side of the barrier layer.
Claim 9
Dependent Claim
109 words
The magnetic head comprising: a magnetic field sensor having a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the magnetic head further comprising a magnetic yoke for cooperation with the magnetic tunnel junction device.
Claim 10
Dependent Claim
109 words
The magnetic head comprising: a magnetic field sensor having a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the magnetic head further comprising a magnetic yoke for cooperation with the magnetic tunnel junction device.
Claim 11
Dependent Claim
41 words
The head according to claim 7 , in which: the material of the intermediate layer includes a metal of a group including: Cs, Ba, Sr and Y; and the intermediate layer is only provided on one side of the barrier layer.
Claim 12
Independent Claim
115 words
A system for reading information from a magnetic information carrier, the system comprising: a magnetic field sensor with a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the system further comprising an output for information read from the information carrier.
Claim 13
Independent Claim
115 words
A system for reading information from a magnetic information carrier, the system comprising: a magnetic field sensor with a transducer element formed by a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the system further comprising an output for information read from the information carrier.
Claim 14
Dependent Claim
40 words
The system according to claim 9 , in which: the material of the intermediate layer includes a metal of group including: Cs, Ba, Sr and Y; and the intermediate layer is only provided on one side of the barrier layer.
Claim 15
Dependent Claim
100 words
A magnetic tunnel junction memory cell comprising: a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the memory cell further comprising an output for information stored in the memory cell.
Claim 16
Dependent Claim
100 words
A magnetic tunnel junction memory cell comprising: a magnetic tunnel junction device including: a pair of electrode layers of a ferromagnetic material; a tunnel barrier layer of an insulating material, interposed between the electrode layers; and an intermediate layer provided between the tunnel barrier layer and one of the electrode layers, which intermediate layer includes a conductive material having a work function with a value which is at least 25% lower than a value of a work function of the material of the one electrode layer; the memory cell further comprising an output for information stored in the memory cell.
Claim 17
Dependent Claim
41 words
The device according to claim 11 , in which: the material of the intermediate layer includes a metal of a group including: Cs, Ba, Sr and Y; and the intermediate layer is only provided on one side of the barrier layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-09-24 | 2005-03-26 | 2005-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-24 | 2009-03-26 | 2009-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-24 | 2013-03-26 | 2013-09-25 | $7700.00 | Window Closed / Lapsed |