MRAM stands for Magnetoresistive Random Access Memory. It is a technology whose time has not yet come, mainly because it hasn't been needed yet. Many experts believe, however, that MRAM is on the horizon and will be implemented any time now.
As its name suggests, MRAM uses magnetic storage elements to store its data. Specifically, two iron plates sandwich a thin insulating layer. One of those plates is a magnet that is set to a specific charge. The other plate is variable, allowing for changing polarity according to external fields' pull. A collection of these elements make up the MRAM memory device.
Like other RAM, MRAM consists of data. In this case, the data is written into the MRAM system using magnetic fields. Because MRAM writes and stores this data using magnetic fields rather than traditional electrical circuitry, it requires much less power than other comparable systems of memory storage.
Dynamic RAM (DRAM), which is the industry standard because of its superior density and price point, is less attractive when compared to MRAM because of MRAM's ability to store and refresh data using minimal power and a lower current. MRAM also compares favorably to flash memory in that MRAM does not degrade during writing and suffers no read-write speed irregularities. The biggest benefit of MRAM, however, is that the data is stored in the chip as long as the magnetic charge holds. Unlike electrical circuits, which lose their data "memory" when a computer is powered off, MRAM circuits can retain data long after shutdown.
MRAM is on the way, many experts believe. Such major companies as Sony, Toshiba, and NEC have introduced prototype MRAM chips. These prototypes are not up to the speed and density specs of DRAM and Flash yet, but they will be. Look to see MRAM chips in the next decade or so powering such things as digital cameras, mobile telephones, notebook computers, cellular base stations, and even aerospace and military systems.