New Memory Technology

Sunday, January 8, 2017

New Memory Technology
Rebecca Reilly

Computers can use as many as four different kinds of memory technology like hard drives and memory chips. However, each of these drives have their weaknesses. Now, engineers are working on a new memory technology that has unique features. This new technology goes by the name STT-MRAM, which stands for spin transfer torque magnetic random access memory. Engineers are hoping that STT-MRAM will have no weaknesses.

Schmidt's lab, one of the 15 partners in the Samsung Global MRAM Innovation program, is working with Samsung researchers to help develop STT-MRAM. Schmidt is using optical techniques based on ultra-short laser pulses to study preproduction prototype devices from Samsung. His studies are helping the company improve their materials and inventing.
STT-MRAM works by storing information in the magnetic states of tiny magnetic elements less than 100 nanometers.

Unlike hard drives, STT-MRAM devices use electric current to read and write data. Even though improvements are still being made, this technology has the potential for high speed, high density, energy efficient memory that will save information when the power is cut out. Key advances in physics over the past two decades have led to the development of STT-MRAM and other spintronic technologies. Spintronics uses another property of electrons called spin which is one of those bizarre concepts of quantum mechanics. With spin, electrons behave as if they were spinning, producing a small magnetic moment that can interact with other electrons and atoms in a material.

The nano magnets in an STT-MRAM device, known as spin valves, have two magnetic layers separated by a thin barrier so that electric current can flow. When the spins in the two magnetic layers are aligned, the resistance becomes low, and if the two layers have opposite spins, the resistance becomes high providing tow readable and switchable states to represent 0 and 1 in binary logic of computers.


STT-MRAM chips are beginning to reach the market, and dozens of companies are working to use the technology for use in consumer electrons. According to Schmidt, the challenge is to operate the chips with as little power as possible, so that they don't heat up as much. Schmidt explained that how much current a chip takes to switch a nano magnet depends on how long it takes to settle down into a new spin state, or damping. Measuring damping parameters in an array of nano magnets is hard, but Schmidt's lab is able to do this with laser pulses. The collaboration with Samsung has helped Schmidt improve STT-MRAM and help it get to its potential.