Volume 77, Number 2, January 2007
Article Number 20008
Number of page(s) 5
Section General
Published online 22 January 2007
EPL, 77 (2007) 20008
DOI: 10.1209/0295-5075/77/20008

New magnetic effects on the phase transitions in unconventional superconductors

D. I. Uzunov

Max-Plank-Institut für Physik komplexer Systeme - Nöthnitzer Str. 38, 01187 Dresden, Germany CP Laboratory, Institute of Solid State Physics, Bulgarian Academy of Sciences - BG-1784 Sofia, Bulgaria

received 8 September 2006; accepted in final form 21 November 2006; published January 2007
published online 22 January 2007

The effect of magnetic fluctuations on the critical behaviour of unconventional ferromagnetic superconductors (UGe2, URhGe, etc.) and superfluids is investigated by the renormalization group method. For the case of isotropic ferromagnetic order a new unusual critical behaviour is predicted. It is also shown that the uniaxial and bi-axial magnetic symmetries produce fluctuation-driven phase transitions of first order. The results can be used in interpretations of experimental data and for a further development of the theory of critical phenomena in complex systems.

05.70.Jk - Thermodynamics: Critical point phenomena.
74.20.De - Superconductivity: Phenomenological theories (two-fluid, Ginzburg-Landau, etc.).
75.40.Cx - Magnetic properties and materials: Static properties (order parameter, static susceptibility, heat capacity, critical exponents, etc.).

© Europhysics Letters Association 2007