An unusually unsymmetrical organometallic complex made up of an erbium atom sandwiched between two different aromatic hydrocarbon rings exhibits unique magnetic behavior, a new study shows. This complex could become a prototype for further development of single-molecule magnets (SMMs), which are being sought for applications such as high-density information storage and quantum computing.
Conventional magnets rely on the collective behavior of the unpaired electron spins of millions of individual metal atoms in a bulk material. SMMs, on the other hand, individually exhibit magnetlike behavior. A magnetic device made with these complexes, each storing a bit of data, could hold thousands of times more information than current storage devices.
Most SMMs are based on cluster compounds with multiple metal-ion cores such as Mn12O12, but only about 10 examples of single-metal-ion SMMs are known. A research team led by Song Gao and Bing-Wu Wang of Peking University, in China, has synthesized and studied the magnetic properties of a new type: an erbium cyclooctatriene pentamethylcyclopentadiene complex (J. Am. Chem. Soc., DOI: 10.1021/ja200198v).
Researchers at the Consejo Superior de Investigaciones Cientificas (CSIC) have developed a novel atomic force method called bimodal force microscopy to simultaneously detect short and long-range forces of different nature. The method is applied to image protein-based magnetic particle carriers in air and liquid with a 5 nm spatial resolution.
The CSIC team has discovered a new nanomechanical process based on the coupling of two resonances of the force microscope microcantilever to identify and separate short- and long-range interactions. The coupling is mediated by the nonlinear character of the tip-surface forces. The technique enables the detection of a minimum magnetic moment around 50 µB in a ferritin molecule with an estimated size of 5 nm. It reaches a lateral magnetic resolution below 7 nm in liquid.
The team presented its work in the journal Nanotechnology.
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A Kiel research group headed by the chemist, Professor Rainer Herges, has succeeded for the first time in directly controlling the magnetic state of a single molecule at room temperature, as reported in the Science article "Magnetic Bistability of Molecules in Homogeneous Solution at Room Temperature". The switchable molecule, which is the result of a sub-project of the Collaborative Research Centre 677 "Function by Switching", could be used both in the construction of tiny electromagnetic storage units and in the medical imaging.
The record player molecule is shown here as a model. The arrows symbolise the magnetic state in the nickel ion which can be directly switched by contact with the nitrogen atom on the 'tone arm'. Irradiating the molecule with blue-green light, the nitrogen atom is placed vertically to the nickel ion, which becomes magnetic, because the pairing of the two electrons is cancelled out. This reaction can be repeated thousands of time, without side reactions.
The switch with its diameter of only 1.2 nanometres could be used as a tiny magnetic reservoir in molecular electronics. Most of all, hard disk manufacturers may be interested in this, as a higher storage capacity can be achieved by reducing the size of the magnetic particles on the surface of the disks.
Guenter Mistelberger just published an excellent review article about luminescent magnetic particles. Very useful for anybody who uses them in life science applications such as multimodal imaging, analyte monitoring, nanotherapeutics, and combinations thereof. Have a look at it here.
After every "Magnetic Carrier Meeting", we publish peer reviewed articles in a special journal issue that contains the most-up-to date research in our area. This year we did that with the American Institute of Physics in theirConference Proceeding Series. This AIP publication is well indexed and you can easily find your papers with search engines such as SciFinder.
We would like to announce here that our peer reviewed proceedings have just been published as the AIP Conference Proceedings 1311
This year, it is a fully digital version, and we will not send out a hard copy. The conference proceedings consist of 68 full size peer-reviewed publications, totalling exactly 500 pages. Lots of interesting articles about magnetic particles and their applications.
You can access all articles here.
Nguyen T. K. Thanh et al. just got a special issue about nanoparticles published in thePhilosophical Transactions of the Royal Society A. The theme issue includes articles on the synthesis of cobalt sulphide nanostructures, CoCuPt hollow and Ag@Au core–shell nanoparticles as well as thin films at water–oil interfaces. Colloidal templates for copolymer micelles and porous silica are also covered. More exotic synthetic methods include high-throughput hydrothermal flow synthesis of Zn–Ce oxides. Sensing magnetic nanoparticles with a tunneling magnetoresistance sensor is another aspect of the research covered as well as applications of La1−xSrxMnO3 nanoparticles for magnetic fluid hyperthermia. Many of the articles include detailed characterization of nanoparticles in order to better understand structure– function relationships; a fine example of which includes investigations of magnetic properties of nanoparticles owing to size and surface effect. Finally, useful nanoparticle characterization techniques such as magnetic field-flow fractionation and light scattering are also covered.
Check it out at http://rsta.royalsocietypublishing.org/content/368/1927.
Do you remember the excellent tutorial that Kannan Krishnan gave at our 8th Magnetic Carrier Meeting in Rostock? And now the paper that goes with it is available. Kannan describes in there that biomedical nanomagnetics is a multidisciplinary area of research in science, engineering and medicine with broad applications in
imaging, diagnostics and therapy. Recent developments offer exciting possibilities in personalized medicine provided a truly integrated approach, combining chemistry, materials science, physics, engineering, biology and medicine, is implemented. Emphasizing this perspective, Kannan addresses important issues for the rapid development of the field, i.e., magnetic behavior at the nanoscale with emphasis on the relaxation dynamics, synthesis and surface functionalization of nanoparticles and core-shell structures, biocompatibility and toxicity studies, biological constraints and opportunities, and in vivo and in vitro applications.
Do you remember the excellent tutorial that Kannan Krishnan gave at our 8th Magnetic Carrier Meeting in Rostock? And now the paper that goes with it is available.
Kannan describes in there that biomedical nanomagnetics is a multidisciplinary area of research in science, engineering and medicine with broad applications in
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