My name is Carl Rau. I am Professor of Physics in the Department of
Physics & Astronomy at
I am teaching, researching and consulting in the areas of surface- and nanophysics, spintronics, nanomagnetism, non-volatile MRAM research, magnetic nano-sensors, domain wall propagation in arrays of magnetic nanowires, scanning tunneling microscopy, spin mapping of micromagnetic magnetization patterns by using scanning ion microscopy with polarization analysis (SIMPA), high-resolution magnetic domain imaging, nanolithography, focused ion beam (FIB) creation of nano-patterned magnetic systems,etc.. We are working in the Anderson Biology Laboratories in Room 219.
By the way, the name of our dog is Alex von Wyld
Wings, and he is a well-trained German Short-Haired Pointer. His
father's name is Hasko Rothenuffeln.
He is a famous champion in
Alex is now 15 years old, and we are very proud of him.
Some of my hobbies are hunting, fishing, jogging, hiking, taking photographs, and Tae Kwon Do (black belt, 3. Dan in WTF).
If you want to send me e-mail, send it to: Carl
The first Rau's came to America in 1520. Greetings from some of my ancestors
If you would like to work in my research group, please click here:
You are visitor # since March 19, 1999.
Here is a link to Microsoft.
Here is a list of some selected publications with links
Here are recent scientific breakthroughs:
Tiny vortex could be key to computing future
In a research first that could lead to a new generation of hard drives capable of storing thousands of movies per square inch, physicists at Rice University have decoded the three-dimensional structure of a tornado-like magnetic vortex no larger than a red blood cell.
“Understanding the nuances and functions of magnetic vortices is likely going to be a key in creating next-generation magnetic storage devices,” said lead researcher Carl Rau, professor of physics and astronomy. “It’s widely believed this technology will support storage densities in the range of terabits per square inch, and our group is equally excited about the potential for magnetic processors and for high-speed magnetic RAM.”
The findings are available online and due to appear in an upcoming issue of Physical Review Letters.
Rau and postdoctoral researcher Jian Li used a one-of-a-kind scanning ion microscope to first create and then measure ultra-thin circular disks of soft magnetic cobalt. Their goal was to trap and image a single magnetic vortex, a cone-like structure that’s created in the magnetic field at the disk when all the magnetic moments of the atoms in the disk align into uniform concentric circles. However, toward the core of the disk, the magnetic moments point more and more out of the plane of the disk, like a swirling cone. If the vortex spins in a right-handed direction, the cone points up; if the vortex spins left, the cone points down.
In searching for the right sized disk to create the phenomenon, Rau and Li used thin films of cobalt — about the thickness of a cell membrane. They made disks with diameters as large as 38 microns — about half the width of a human hair — and as small as one micron. The single vortex was found on disks measuring 6 microns in diameter, slightly smaller than a red blood cell.
“Most people are familiar with the vortex,” Rau said. “We see it in satellite photos of hurricanes, in whirlpools and in bathtub drains — even in Van Gogh’s famous painting ‘Starry Night.’ In nanomagnetism, however, vortices are quite hard to see experimentally. Most often, we must infer their existence from some other measurement.
“Our high-resolution spin microscope is the exception here,” he said. “It allows us to map not just the overall vortex, but also the detailed location and orientation of millions of magnetic moments that combine physical forces to create the overall structure.”
The instrument Rau and Li used in the study is a scanning ion microscope with polarization analysis, or SIMPA. The device consists of a highly focused ion beam that fires gallium ions at surfaces of flat cobalt samples. The beam is first used to etch away the cobalt around each circular disk. Then the gallium ions are fired at the cobalt surface in such a way as to induce the release of electrons. The electrons, which carry specific information about the magnetic state of the cobalt atoms that release them, are captured by a detector and analyzed.
Rau said better understanding of magnetic vortices could allow breakthroughs in the design of nanostructures for ultra-high-density hard-disk media, nonvolatile magnetic RAM and novel magnetic logic gates that could replace volatile semiconductor logic. Compared to regular electronic devices, the magnetic devices would be faster, smaller, use less power, create less heat and they wouldn’t lose information when power was turned off.
“Imagine if you never had to reboot your computer again,” Rau said.
The research was supported by the National Science Foundation.
(see article in the Rice News by Jade Boyd)
published in Physical Review Letters
3D spin-vortex map (contour plot of the out-of-plane component of the vortex magnetization)
of a focused ion beam created, 6 mm diameter, 30nm thick Co nano-disk.
Rice News by Jade Boyd: Tiny vortex could be key to computing future
PHYSORG.com: Physicists trap, map tiny magnetic vortex
ScienceDaily: Physicists trap, map tiny vortex: Cell-sized 3D structure could hold key for next-gen hard drives.
PCMAG.COM: Terabits In The Vortex
Inovacao Tecnológica, Brasil: Vórtices magnéticos tridimensionais poderão ser caminho para super discos rígidos
Sallyport, Rice: Vortex Computing
MAGAZIN STIINTIFIC, Romania: Urmeaza o nou generatie de hard-discuri
PCTUNER FORUM, Italy: Metti un tornado nell'hard disk
United Nations University, Merit, Netherlands: Physicists trap, map tiny magnetic vortex
Physics and Energy, Breakthroughs in Physics, Canada: Physicists trap, map tiny magnetic vortex