Memory - Page 9

Researchers at the Max Planck Institute of Microstructure Physics in Halle developed a new switching mechanism for magnetic current. The idea is to use a short electric pulse to change the magnetic transport properties of a material sandwich consisting of a ferroelectric layer between two ferromagnetic materials. The new mechanism could be used to store information in four states of a storage point, not just two - which doubles storage density or lowers the size of MRAM devices.

In ferroelectric materials, voltage switches between the two directions of an electric polarisation – depending on its polarity – not unlike when a magnetic field permanently reverses the polarity of a ferromagnet. As ions shift within the material structure during this process, the polarisation remains intact, even after the voltage has been reduced. It is possible, however, to reverse the switch again with a similarly large voltage with reversed polarity.

Tohoku University and Tokyo Electron announced that they will jointly develop Spintronics memory integration and manufacturing technology. Professor Tetsuo Endoh from Tohoku's Center for Spintronics Integrated Systems (CSIS) will lead the research. The aim of this project is to present a miniature highly-integrated Spintronics memory device and the process technologies needed to commercially manufacture it.

The CSIS is considered one of the world's leaders in Spintronics memory, and will contribute its magnetic material technologies, device technologies and design technologies. TEL will contribute process and equipment technologies. The video above shows the Spintronics IC work done at the CSIS.

Researchers from the Physical and Technical Institute in Braunschweig, Germany have discovered that waste heat can be used inside magnetic tunnel structures (such as those used in MRAM chips). This means that such structures may be used to monitor and control "thermoelectric voltages" and currents in highly integrated electronic circuits.

In their experiments, the scientists generated a temperature difference between the two magnetic layers and investigated the electric voltage (or "thermoelectric voltage") generated hereby. It turned out that the thermoelectric voltage depends on the magnetic orientation of the two layers nearly as strongly as the electric resistance. By switching the magnetization, it is therefore possible to control the thermoelectric voltage and, ultimately, also the thermal current flowing through the specimen.

Researchers from the National Institute of Standards and Technology (NIST) and University of Colorado Boulder (CU) developed a new chip that uses microfluidics and magnetic switches to trap and transport magnetic beads. This low-power device may be useful for medical devices. This technology may also lead us towards "MRAM" chips used for molecular and cellular manipulation.

In the past, magnetic particle transport chips required continuous power and even cooling. This new technology manages to overcome the power and heat issues, and offers random-access two-dimensional control and non-volatile memory. The prototype chip uses 12 spin valves (commonly used as magnetic sensors in HD read heads) which are optimized for magnetic trapping. Pulses of electric current are used to switch individual spin valve magnets “on” to trap a bead, or “off” to release it, and thereby move the bead down a ladder formed by the two lines. The beads start out suspended in salt water above the valves before being trapped in the array.

Researchers from Europe developed a graphene based device that can detect magnetic fields with a record sensitivity (down to the stray field of few magnetic molecules, better than the previous record of sensitivity by a factor of 100). The graphene was used like a spider web to chemically 'trap' the molecules and detect their magnetization at the same time. This new development may enable ultra-high density Spintronics memory and molecular sensors.

Researchers from Japan discovered that dilute ferromagnetic oxide materials remain in a ferromagnetic state at room temperature. The team used cobalt-doped titanium dioxide (Co:TiO2) as their study material. This means hat magnetism and conductivity are correlated in thin films of Co:TiO2. Such materials may plan an important role in spintronic devices (MRAM or spin transistors).

There's a new science called Atomtronics - which could make devices more powerful than electronics or spintronics. The idea is to use super-cooling atoms that form Bose-Einstein condensates ('gas clouds') and then use them as we use electronics, diodes and transistors. The atoms in the condensate flow as a current, which can be switched on and off like a normal circuit.

This is still all in theory, but there are some scientists already working towards such goals - to create powerful computing devices or memory devices. This is different from spintronics, which stores information based on the spin of individual electrons, allowing each one to store two bits of data instead of one.

Watch David Awschalom, a Spintronics pioneer, in a great talk at TEDxCaltech titled "Spintronics: Abandoning Perfection for the Quantum Age". This is a great introduction to Spintronics:

IBM reports some advances in their racetrack memory program, and they are now able to measure the movement and processing of data as a magnetic pattern on a nanowire (which is 1,000 finer than a human hair).

Racetrack memory uses electron spin to move data on nanowires at hundreds of miles per hour - and has the potential to be very lower power with high densities.

Paul Haney and Mark Stiles from the NIST Center for Nanoscale Science and Technology (CNST) developed a new theory of current-induced torques that generalizes the relationship between spin transfer torques, total angular momentum current, and mechanical torques. This new theory is also applicable to more materials than previous theories.

The basic idea is that there are two types of current-induced torques: a mechanical torque acting on the lattice, and a spin transfer torque (STT) acting on the magnetization. STT is a known phenomenon that is the basic of several technologies such as STT-MRAM and nanoscale microwave oscillators.