Press releases
Please quote Nature Materials as the source of these items.
March 2007
Next-generation glass
A glass that spontaneously forms from sugar and oil may be the starting point for a whole new class of materials with unique properties, according to an article published online this week in Nature Materials.
Carlos Co and colleagues explored oil as an alternative to water as the medium for forming emulsions. They put sugar in oil, along with some surface-active molecules, heated the mixture until the sugar melted, and then waited for the whole thing to cool down. The transparency and solid consistency of the glasses that form belie the inclusion of more than 50 volume percent of oil. The oil gives these materials liquid-like behaviour, which, combined with their solid-like characteristics, provide a whole new set of properties. The authors envisage that these glasses might find applications as sensors and optical devices, particularly in the pharmaceutical and food industry. But because they are so different from anything else, they could even inspire applications that do not yet exist.
Self-assembly in sugar-oil complex glasses
Hiteshkumar Dave, Feng Gao, Jing-Huei Lee, Matthew Liberatore, Chia-Chi Ho & Carlos C. Co
Published online: 25 March 2007 | doi 10.1038/nmat1864
Protein sensing in full colour
A sensor for proteins that is so sensitive it can detect changes in concentration spanning more than five orders of magnitude is reported in the April issue of Nature Materials. Most biosensors rely on changes in the intensity of the fluorescence emitted, which is difficult to calibrate, but Nicholas Kotov and colleagues present a device where the wavelength of the emitted light shifts reversibly.
The device is based on gold nanoparticles that are attached to nanowires using molecular springs that carry protein-binding antibodies. As soon as the target protein attaches to the antibody, the molecular spring extends and moves the nanospheres further away from the nanowire - reducing the interaction between sphere and wire. This leads to noticeable changes in the wavelength of the light emitted from the nanowire, and this effect can therefore be used as a molecule-specific biosensor. The ease of calibration as well as the broad range of sensitivities suggests the potentially widespread use of this nanotechnology sensor in a large variety of biological applications.
Exciton-plasmon interactions in molecular spring assemblies of nanowires and wavelength-based protein detection
Jaebeom Lee, Pedro Hernandez, Jungwoo Lee, Alexander O. Govorov & Nicholas A. Kotov
Published online: 25 March 2007 | doi 10.1038/nmat1869
Reversing the magnetic vortex core
The magnetization direction in a submicrometre magnetic disk can be controlled by an electrical current - according to a report in the April issue of Nature Materials. This work demonstrates the possibility of using the magnetization direction to store data in all-electrically controlled magnetic memory devices.
In a magnetic disk, the magnetization curls around the edges forming a so-called magnetic vortex. However, in the centre of the vortex - the core - the magnetization is forced to point either up or down with respect to the disk plane. Teruo Ono and colleagues have found that an alternating electric current can destabilize the core and turn it upside down, because of the interaction of the electron spin with the magnetic vortex. The up or down directions of the magnetization can be seen as the 1 and 0 states of a binary data storage bit.
Electrical switching of the vortex core in a magnetic disk
Keisuke Yamada, Shinya Kasai, Yoshinobu Nakatani, Kensuke Kobayashi, Hiroshi Kohno, André Thiaville and Teruo Ono
Published online: 18 March 2007 | doi 10.1038/nmat1867
Multiferroics as the ultimate memory?
Multiferroic materials - a rare class of materials where electric and magnetic fields are coupled - could hold the key to achieve a memory device that is capable of storing large amounts of data within a very small amount of space, suggests a report to be published online this week in Nature Materials.
Manuel Bibes and colleagues investigated a device where electrons travel through a very thin multiferroic layer. Depending on the electric and magnetic fields in this layer, the electrical resistance across the film changes, which can be used as the fundamental element of a memory device. Crucially, the coupling of electric and magnetic fields in the multiferroic film means that the device could be electrically or magnetically written and electrically read. The present approach represents significant technological progress compared with commercial ferroelectric and magnetic memories, as it combines the advantages of both technologies, while avoiding their disadvantages.
An accompanying News & Views article by James Scott suggests that the advance achieved has the potential of a ‘disruptive technology’ that could overturn existing memory device concepts, and might lead to the widespread commercialization of multiferroics.
