Multiferroics and Toroidal moments in magnets

Some articles on the currently active issue of Mutiferroics and toroidal moments in magnets:

1) Multiferroicity: the coupling between magnetic and polarization orders (A Review).
K.F. Wangab, J.-M. Liuab and Z.F. Renc
Advances in Physics 58, 321(2009)

2) Hypertoroidal moment in complex dipolar structures.
S. Prosandeev, L. Bellaiche
J. Mater. Sci. 44, 5235 (2009)

3) A system exhibiting toroidal order.
A. B. Harris
Phys. Rev. B 82, 184401 (2010)

4) Towards a microscopic theory of toroidal moments in bulk periodic crystals.
Claude Ederer, and Nicola A. Spaldin
Phys. Rev. B B 76, 214404 (2007)