title: Production, detection, storage and release of spin currents.
abstract: BACKGROUND
  Quantum rings connected to ballistic circuits couple strongly to external magnetic fields if the connection is not symmetric. Moreover, properly connected rings can be used to pump currents in the wires giving raise to a number of interesting new phenomena. At half filling using a time-dependent magnetic field in the plane of the ring one can pump a pure spin current, excited by the the spin-orbit interaction in the ring.
  
  
  RESULTS
  Such a magnetic current is even under time reversal and produces an electric field instead of the usual magnetic field. Numerical simulations show that one can use magnetizable bodies as storage units to concentrate and save the magnetization in much the same way as capacitors operating with charge currents store electric charge. The polarization obtained in this way can then be used on command to produce spin currents in a wire. These currents show interesting oscillations while the storage units exchange their polarizations.
  
  
  CONCLUSIONS
  The magnetic production of spin currents can be a useful alternative to optical excitation and electric field methods.
authors.affiliation: Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Rome, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Cini
keywords: quantum pumping; quantum transport; spin current
references.citation: Phys Rev Lett. 2000 Dec 18;85(25):5432-5
references.pmid: 11136014
references.citation: Phys Rev Lett. 2010 Oct 8;105(15):156802
references.pmid: 21230926
references.citation: J Phys Condens Matter. 2014 Apr 9;26(14):145301
references.pmid: 24637301
references.citation: Phys Rev Lett. 2000 Jul 10;85(2):393-6
references.pmid: 10991291
references.citation: Nature. 2011 May 26;473(7348):493-6
references.pmid: 21614077