New RAM Technology Promises Faster, Cheaper And More Energy Efficient Computing

A newly commercialized data storage technology promises to combine the best features of hard disk drives and random access memory to deliver faster computer performance at a lower cost and with less power consumption. Using what's known as spin-transfer-torque magnetic random access memory (SST-MRAM), computer memories may finally be able to have their cake and eat it too!

The future of data storage?: Everspin is a commercial supplier of SST-MRAMThe future of data storage?: Everspin is a commercial supplier of SST-MRAM

 

The cake in this case is long term, high-density data storage without the need for a constant power supply. This ability to retain information in the absence of externally supplied power is referred to as non-volatile memory and is the principle behind hard disk drives. These drives use small regions of magnetic material as 'bits' in which the direction of magnetization in the material corresponds to either a '0' or a '1'.The information can be read off the disk using a magnetic head which moves over the surface of the disk. This need for a moving mechanical part means that data retrieval from these systems is relatively slow, on the order of milliseconds, and that they are susceptible to mechanical failure.

The eating half of my cake analogy therefore refers to the ability to retrieve data quickly, on a nanosecond time scale, a process typically performed in computers by random access memory. Modern RAM consists of an integrated circuit in which a capacitor is used as the information storage device. The capacitor can exist in either a high charge or low charge state corresponding to either a '1' or a '0' bit. This method allows for rapid data retrieval because the state of the capacitor can be read electrically without the need for a moving magnetic head. On the other hand, it also requires a constant power supply in order to maintain the charge states of the capacitors. For this reason, traditional RAM is referred to as volatile memory.

The development of SST-MRAM is an effort to combine the best features of both of the above -- a magnetic storage system with an electrical read/write system. SST-MRAM uses nanoscale magnets to store information much like a hard drive, but the state of the nanomagnets can be read and manipulated using an electric current. In the past two decades, a key finding in the realm of physics is that a certain type of electrical current, referred to as spin-polarized, can be used to reorient a nano-sized magnet, effectively switching it from a '0' to a '1' or vice versa. This discovery enables the "write" functionality of SST-MRAM devices. The stored bits can also be "read" electrically thanks to the phenomenon of magnetoresistance. When the magnetization of a material changes orientation, the conductivity of the material is also altered allowing the magnetic reorganization to be monitored via the electrical current flowing through the device.

In the past several years, this technology has already reached the point of commercial availability, a remarkable feat for such relatively new science. This rapid pace of development is reflective of the high demand for non-volatile, fast-access memory and suggests that SST-MRAM, and other technologies like it, will only continue to improve and become increasingly prevalent in coming years.