Invention Grant
- Patent Title: Magnetic memory system using MRAM-sensor
- Patent Title (中): 磁记录系统采用MRAM传感器
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Application No.: US11814674Application Date: 2006-01-19
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Publication No.: US07791937B2Publication Date: 2010-09-07
- Inventor: Friso J. Jedema , Hans M. B. Boeve , Jaap Ruigrok
- Applicant: Friso J. Jedema , Hans M. B. Boeve , Jaap Ruigrok
- Applicant Address: NL Eindhoven
- Assignee: NXP B.V.
- Current Assignee: NXP B.V.
- Current Assignee Address: NL Eindhoven
- Priority: EP05100427 20050124
- International Application: PCT/IB2006/050208 WO 20060119
- International Announcement: WO2006/077553 WO 20060727
- Main IPC: G11C11/34
- IPC: G11C11/34

Abstract:
The invention relates to a Magnetic memory system (1, 20) which comprises an information layer (13) and a sensor (2, 22) for cooperating with the information layer (13). The information layer (13) comprises a pattern of magnetic bits (4a, 4b, 4c, 4d, 24a, 24c, 24d) which constitutes an array of bit locations. A bit magnetic field (3a, 3b, 3c, 3d) at a bit location represents a logical value (LO, L1/2, L1). The sensor (2, 22) comprises a magnetoresistive element (6, 26) comprising a fixed magnetic layer (7) and a free magnetic layer (8). The free magnetic layer (8) has a magnetization axis (10) along which the free magnetic layer retains a free magnetization direction (1 Ib, 1 Ic, 21b, 21c). A first bit magnetic field (3b, 3c) at one of the bit locations represents a first logical value (LO, L1/2, L1) by providing a first resistance value (Rmax, Rmid, Rmin) in the magnetoresistive element (6, 26) due to the free magnetization direction (1 Ic, 1 Ib, 21a, 21c) being substantially parallel to the magnetization axis (10). A second bit magnetic field (3a, 3d) at one of the bit locations represents a second logical value (LO, L1/2, L1) by providing a second resistance value (Rmax, Rmid, Rmin) in the magnetoresistive element (6, 26) due to the free magnetization direction (Ha, 1 Id, 21a, 2Id) having an angle (12a, 12d, 27) with the magnetization axis (10). The second bit magnetic field (3a, 3d) which provides the second resistance value (Rmax, Rmid, Rmin) is not one of the two stable magnetization directions of the free magnetic layer (8) and thus is different from the first resistance value (Rmax, Rmid, Rmin). The magnetization direction of the free magnetic layer (8) of the sensor (2, 22) no longer needs to be set before read-out.
Public/Granted literature
- US20080316801A1 Magnetic Memory System Using Mram-Sensor Public/Granted day:2008-12-25
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