These materials exhibit superconductivity in proximity to a magnetic quantum critical point.
Early investigations[5] studied the coexistence of conventional s-wave superconductivity with itinerant ferromagnetism.
[6][7] A mean-field model for coexistence of spin-triplet pairing and ferromagnetism was developed in 2005.
In these cases, the superconducting and magnetic order parameters entwine each other in a spatially modulated pattern, which allows for their mutual coexistence, although it is no longer uniform.
A viable mean-field Hamiltonian for modelling itinerant ferromagnetism coexisting with a non-unitary spin-triplet state may after diagonalization be written as[8][9]