Navigation Links
Shape matters in the case of cobalt nanoparticles
Date:6/17/2009

Shape is turning out to be a particularly important feature of some commercially important nanoparticlesbut in subtle ways. New studies* by scientists at the National Institute for Standards and Technology (NIST) show that changing the shape of cobalt nanoparticles from spherical to cubic can fundamentally change their behavior.

Building on a previous paper** that examined the properties of cobalt formed into spheres just a few nanometers in diameter, the new work explores what happens when the cobalt is synthesized instead as nanocubes. Nanoparticles of cobalt possess large magnetic momentsa measure of magnetic strengthand unique catalytic properties, and have potential applications in information storage, energy and medicine.

One striking difference is the behavior of the two different particle types when external magnetic fields are applied and then removed. In the absence of a magnetic field, both the spherical and cubic nanoparticles spontaneously form chainslining up as a string of microscopic magnets. Then, when placed in an external magnetic field, the individual chains bundle together in parallel lines to form thick columns aligned with the field. These induced columns, says NIST physicist Angela Hight Walker, imply that the external magnetic fields have a strong impact on the magnetic behavior of both nanoparticle shapes.

But their group interactions are somewhat different. As the strength of the external field is gradually reduced to zero, the magnetization of the spherical nanoparticles in the columns also decreases gradually. On the other hand, the magnetization of the cubic particles in the columns decreases in a much slower fashion until the particles rearrange their magnetic moments from linear chains into small circular groups, resulting in a sudden drop in their magnetization.

The team also showed that the cubes can be altered merely by observing with one of nanotechnologys microscopes of choice. After a few minutes exposure to the illuminating beam of a transmission electron microscope, the nanocubes melt together, forming nanowires that are no longer separable as individual nanoparticles. The effect, not observed with the spheres, is surprising because the cubes average 50 nm across, much larger than the spheres 10 nm diameters. You might expect the smaller objects to have a lower melting point, Hight Walker says. However, the sharp edges and corners in the nanocubes could be the locations to initiate melting.

While Walker says that the melting effect could be a potential method for fabricating nanostructures, it also demands further attention. This newfound effect demonstrates the need to characterize the physico-chemical properties of nanoparticles extremely well in order to pursue their applications in biology and medicine, she says.


'/>"/>

Contact: Chad Boutin
boutin@nist.gov
301-975-4261
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology news :

1. Facial attraction -- choice of sexual partner shaped the human face
2. Shape encoding may start in the retina
3. Grant supports study of abnormal ring-shaped chromosomes
4. Secure Services Corp. Achieves Milestone in United States Identity Protection with the Launch of the SSC SHAPE Card Management Solution
5. How cells keep in shape
6. New process makes nanofibers in complex shapes and unlimited lengths
7. Particle accelerator may reveal shape of alternate dimensions
8. Crop scientists discover gene that controls fruit shape
9. Ozone hole recovery may reshape southern hemisphere climate change
10. Study links low-frequency hearing to shape of the cochlea
11. Courtship pattern shaped by emergence of a new gene in fruit flies
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Shape matters in the case of cobalt nanoparticles
(Date:4/18/2017)... a global expert in SoC-based imaging and computing solutions, has developed ... the company,s hybrid codec technology. A demonstration utilizing TeraFaces ® , ... showcased during the upcoming Medtec Japan at Tokyo Big Sight April ... Vegas Convention Center April 24-27. ... Click here for an image of the M820 ...
(Date:4/11/2017)... BEACH GARDENS, Fla. , April 11, 2017 ... identity management and secure authentication solutions, today announced ... contract by Intelligence Advanced Research Projects Activity (IARPA) ... for IARPA,s Thor program. "Innovation has ... onset and IARPA,s Thor program will allow us ...
(Date:4/6/2017)... April 6, 2017 Forecasts by ... Document Readers, by End-Use (Transportation & Logistics, Government & ... Gas & Fossil Generation Facility, Nuclear Power), Industrial, Retail, ... Are you looking for a definitive report ... ...
Breaking Biology News(10 mins):
(Date:7/26/2017)... ... July 26, 2017 , ... ... solutions, today announced that its Anzo Smart Data Lake® (Anzo SDL) product ... Information Industry Association (SIIA) CODiE Awards. , Cambridge Semantics’ Anzo SDL uses ...
(Date:7/26/2017)... ... July 25, 2017 , ... In this ... understanding of the considerations needed for designing ideal guide RNAs and DNA oligo ... to create targeted double-strand breaks in genomic DNA has greatly simplified strategies for ...
(Date:7/26/2017)... and REHOVOT, Israel (PRWEB) , ... July 26, ... ... TASE: EVGN), a leading company for the improvement of crop productivity and economics ... into a multiyear collaboration. The scope of the agreement includes the research and ...
(Date:7/24/2017)... ... July 24, 2017 , ... Charm Sciences, Inc. is pleased to ... National Conference on Interstate Milk Shipments (NCIMS) Laboratory Committee and Appendix N Committee as ... July 1, 2017. , The NCIMS voted at its annual meeting in April, 2015 ...
Breaking Biology Technology: