2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/135342Novel vortex phase and nature of double transition field are investigated by two-component Ginzburg-Landau theory in a situation where fourfold-twofold symmetric superconducting double transition occurs. The deformation from 60 degree triangular vortex lattice and a possibility of the vortex sheet structure are discussed. In the presence of the gradient coupling, the transition changes to a crossover at finite fields. These characters are important to identify the multiple superconducting phase in PrOs_4_Sb_12.4 pages, 4 figures, to appear in Phys. Rev. LettSuperconductivitytext