Research Highlights

Cool crystal

doi:10.1038/nindia.2008.342 Published online 28 December 2008

Researchers have stumbled upon wonderful properties of a single spherical niobium crystal when cooled at extremely low temperature. The crystal simultaneously showed surface superconductivity and positive paramagnetic response1. The crystals might have potential application in particle accelerators.

At extremely low temperature, the electrical resistance of the crystals becomes zero and they turn into superconductors. An unavoidable reaction occurs while growing a single crystal in a container. To overcome this, the researchers grew a single spherical crystal of niobium in a containerless condition. For this, niobium crystals were cooled at a temperature of around 9.3 K in the presence of electrostatically charged flux and laser irradiation in high vacuum.

For the first time, the study results show simultaneous appearance of surface superconductivity and positive paramagnetic response (magnetisation only in the presence of externally applied magnetic field). The Nb spheres also showed magnetic flux compression thus offering an alternative to ferromagnetic materials.

Nb spheres could be cooled for use inside particle accelerators and might also find use in magnetic lenses, says lead researcher Arun K. Grover.

The authors of this work are from: Department of Physics, Indian Institute of Technology Bombay, Mumbai, India; Department of Physics, Indian Institute of Technology, Kanpur, India; National Institute of Materials Science, Ibaraki, Japan; Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India.


References

  1. Das, P. et al. Surface superconductivity, positive field cooled magnetization, and peak-effect phenomenon observed in a spherical single crystal of niobium. Phys. Rev. B. 78, 214504 (2008) | Article |