Magnetic storage device

US7218550B2 · kind B2 · utility

Inventors

• Nikolai Franz Gregor Schwabe · Felton, GB
• Carsten Heide · Netphen, DE
• Roger Elliott · Abingdon, GB

Key dates

• Filing date: Jun 24, 2004
• Grant date: May 15, 2007
• Expiry date: Aug 8, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G11C11/16
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A magnetic storage device comprises an array of magnetic memory cells (50). Each cell (50) has, in electrical series connection, a magnetic tunnel junction (MTJ) (30) and a Zener diode (40). The MTJ (30) comprises, in sequence, a fixed ferromagnetic layer (FMF) (32), a non-magnetic spacer layer (33), a tunnel barrier layer (34), a further spacer layer (35), and a soft ferromagnetic layer (FMS) (36) that can change the orientation of its magnetic moment. The material type and thickness of each layer in the MTJ (30) is selected so that the cell (50) can be written by applying a voltage across the cell, which sets the orientation of the magnetic moments of the FMF (32) and FMS (36) relative to one another. The switching is effected by means of an induced exchange interaction between the FMS and FMF mediated by the tunneling of spin-polarised electrons in the MTJ (30). The cell (50) therefore has low power consumption during write operations allowing for fast writing and dense integration of cells (50) in an array. The mechanism used to control the array to write and sense the information stored in the cells (50) is simplified.