News

posted on 14 August 2008 09:57

German researchers have demonstrated Magnetoresistive RAM (MRAM) switching thirty times faster than DRAM and ten times quicker than current MRAM technology. It could lead to much faster computer operation.

Current DRAM represents a binary one or zero via charge stored in a capacitor. MRAM represents it via the direction of a magnetic field. This direction is changed via electron spin in an MRAM technology called STT-RAM or Spin Transfer Torque RAM. Generally each MRAM cell has two magnets in it; one with a fixed field and the other with a variable field. The north-south direction of the variable field can be changed by send a current in a particular way through it. The overall magnetic field direction of the cell can be discerned by directing a current through both magnets.

German researchers at three institutions: the Physical-Technical Federal Laboratory of Germany; the University of Bielefeld; and Singulus Nano-Deposition Technologies, have built cells with the magnets at opposite ends of a 165 nanomer pillar. The fixed magnet is conceptually at the bottom and the variable one at the top. A current flowing from bottom to top has its electrons' spin direction set by the direction of the fixed magnet's field. These electrons then change the variable magnet's direction to match it. A reverse direction current reverses the variable magnet's field direction.

It's the variable magnet's field direction that signifies a binary one or zero. Generally the variable magnet field direction changes take time to become stable as the magnetic field there wobbles about. By tuning the parameters of the current the researchers reduced the time, and the wobbles, by a factor of ten to 1 nanosecond.

Current MRAM product needs 10ns to switch state. DRAM requires 30ns at best for it to register a change in bit value. So, if this new STT-RAM technology was instituted in computers they could have thirty times more memory cycles per second.

The researchers have not yet demonstrated that their technology works with DRAM chip levels of current though.

Hynix is developing STT-RAM and believes it can replace both DRAM and flash as it it is both fast and non-volatile.

More in the New Scientist here.

^{[Martin Edwards, news writer.]}