Ground state of a superconducting π ring array under external magnetic fields
Li Zhuang-Zhi(李壮志)a)b)†, Feng Yun(冯运)c), Wang Fu-Ren(王福仁)a), and Dai Yuan-Dong(戴远东)a)
a Mesoscopic Physics National Laboratory and Department of Physics, Peking University, Beijing 100871, China; b College of Physical Science and Information Engineering,Hebei Normal University, Shijiazhuang 050016, China; c College of Mechanical and Electronic Engineering, Hebei University of Science and Technology, Shijiazhuang 050054, China
Abstract The ground state of a two-dimensional square superconducting $\pi$ ring array has been investigated. The circulating currents of the $\pi$ ring array will spontaneously magnetize to the `antiferromagnetic' arrangement with directions of the nearest-neighbouring currents circulating oppositely in the absence of an external magnetic field. It is found that the external magnetic field could destroy the anti-parallel configuration effectively. The external magnetic field needed to destroy the anti-parallel configuration is related to the superconducting $\pi$ ring's inductance parameter $\beta=2\pi LI_{\rm c}/\phi_0$. For a small $\beta$ the anti-parallel configuration, which is the lowest-energy ground state of the system, will be fully destroyed and changed to the configuration that the circulating currents have the same direction and parallel to the external magnetic field when the magnetic flux reaches $\phi_0/4$ in each ring. Moreover, the magnetic field needed to destroy the anti-parallel configuration will be very small when $\beta$ is large enough.
Received: 25 September 2006
Revised: 04 December 2006
Accepted manuscript online:
PACS:
74.25.Ha
(Magnetic properties including vortex structures and related phenomena)
Fund: Project supported by the State Key
Development Program for Basic Research of China (Grant No
2006CB601007).
Cite this article:
Li Zhuang-Zhi(李壮志), Feng Yun(冯运), Wang Fu-Ren(王福仁), and Dai Yuan-Dong(戴远东) Ground state of a superconducting π ring array under external magnetic fields 2007 Chinese Physics 16 1450
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
