The spontaneous vortex state proposed by Ng and Varma[l] as a co-existence state of superconductivity and magnetization is studied numerically within a Ginsburg-Landau approach, where the H-T phase diagrams for various values of parameters in the G-L free energy functional is obtained. The stability of sponta-neous vortex phase against spiral state is also studied. Furthermore, we consider the case where a phenomenological attraction exists between the superconducting and magnetization order parameters. This situation may arise in double-exchange materials where the electrons can hop only when the background is ferromagnetic. Experimental consequences of our study are discussed.
Permanent URL for this record: https://lbezone.hkust.edu.hk/bib/b645969