Description:
Executive Summary
The invention is a novel method for achieving magnetic random access memory (MRAM) that enables higher memory densities and faster write speeds while lowering the energy consumed when writing to memory.
Background
Although non-volatile computer memory has the ability to store information even when not powered, it is typically disadvantaged by cost or performance when compared to volatile types of memory. MRAM, a type of non-volatile memory, is expected to overcome these disadvantages and potentially displace volatile memory technologies, enabling more energy-efficient computers that can instantly turn on and off.
Attempts to scale MRAM to smaller dimensions, however, have been unsuccessful, limiting its ability to achieve acceptable memory bit densities. This constraint has prevented MRAM from becoming competitive against more commercially successful memory technologies, such as SRAM and Flash.
Invention Description
The present invention is designed to enable smaller-scale, higher-bit density MRAM though a novel approach to bit writing. With this novel technology, a spin torque current induces the “shuttling” of a domain wall back and forth to write the bit. An applied voltage can control the interaction of the multiferroic and the free layer, modulating the coercive field to pin and/or de-pin the magnetization direction, controlling whether the bit is not written or is, respectively.
The free layer can be configured to share multiple magnetic junctions, and a multiferroic at each junction permits the writing of multiple bits with a single current input. As a result, the bit-writing speed is increased and the energy necessary for bit writing is reduced, compared to other MRAM approaches.
Advantages
This technology offers the following advantages over existing technology:
- Spin torque writing enables MRAM to be scaled to dimensions smaller than 65nm for improved memory bit densities
- Sharing of free layers between multiple junctions translates to greater bit-writing capacity and reduced energy usage
- Multiple bit-writing capability provides improved bit-writing speed
Potential Applications
The invention could be used for both short- and long-term storage solutions, potentially displacing hard disk drives and other forms of random access memory. Such use could enable:
- Universal memory for both temporary and long-term storage in personal and commercial computers
- Low-power, high-performance memory for portable devices such as cell-phones and mobile computers
- Computational research and development
