A Flower-Shaped Magnetic Process Opens Doors for Energy-Efficient Memory Devices
What is magnetic skyrmion? And how might it be a key to more power-efficient magnetic memory?
Historically, magnetic memory has been used as a main source of non-volatile memory in computer systems.
Old school forms of magnetic memory use ferromagnetic materials (materials which become permanently magnetized when exposed to magnetic fields) and electrical impulses to store data as binary based on the field’s state. These forms of magnetic memory were mostly found in removable storage devices like hard drives and floppy disks.
Depiction of binary being stored as magnetic states in a hard drive. Image used courtesy of Yale University
Now, with devices scaling down to nanometer length, physicists have been investigating nano-structures, interfaces, and surfaces with the hopes of creating new forms of magnetic memory.
The Pros and Cons of Magnetic Memory
Magnetic memory, like all forms of memory, offers many tradeoffs. One of the greatest draws of magnetic storage is the fact that it’s non-volatile. This means that even when power is removed, the memory states remain. This is important for storage since most forms of memory in computers, such as SRAM and DRAM are volatile.
On the other hand, magnetic storage is generally very power-hungry, and slow to operate. With the hopes of harnessing the benefits while minimizing the cons of magnetic storage, researchers have been looking into new technologies, MRAM being a popular example.
Now with devices on the nano-scale, new forms of magnetic memory based on nano-physics are also emerging. A strong contender in this field is the magnetic skyrmion.
What Is a Magnetic Skyrmion?
A magnetic skyrmion is a quasiparticle that was first predicted theoretically and later observed experimentally. As opposed to the generic “up” or “down” magnetic states, like those used in hard drives, skyrmions offer a flower-shaped state.
This shape—along with other unique features such as their small size, high stability, and ease of manipulation via an electric current—has put skyrmions in the spotlight as a central research topic. Researchers are hopeful that this new technology will allow for low-energy, high-density memory and logic gates in the future.
Potential use of a magnetic skyrmion for memory storage. Image used courtesy of Tohoku University
To this point, devices using skyrmionic technology typically rely on the current-controlled motion of skyrmions. The problem is that this isn’t an energy- or area-efficient technique. Ideally, using skyrmions that are fixed in space could lead to more compact and energy-efficient devices.
Manipulating Fixed Magnetic Skyrmions
In a new study, researchers at Virginia Commonwealth University (VCU) and the University of California, Los Angeles (UCLA) have announced that they’ve come up with a way to manipulate fixed magnetic skyrmions to store data. The technique employs voltage-controlled magnetic anisotropy, as opposed to current-controlled methods.
Image from a magnetic force microscope revealing skyrmions on a fabricated device. Image used courtesy of VCU
Lead researcher Dhritiman Bhattacharya says “our finding demonstrates the possibility of controlling skyrmion states using electric fields, which could ultimately lead to more compact, energy-efficient nanomagnetic devices.”
A Promising Future in Memory Devices
This new research could have large implications on the development of skyrmionic memory. Researchers claim this new technique allows for more dense and energy-efficient memory devices, unlocking much of the potential of this new technology.
While there are still major hurdles to overcome, these findings are a significant accomplishment on the path to transforming memory devices as we know them.
What barriers have you faced in memory device energy efficiency? How have you overcome those barriers? Share your experiences in the comments below.