Upper Critial Field Calculations in p-Wave Tripet Ferromagnetic Superconductors

We report $H_{c2}(T)$ calculations for novel triplet ferromagnetic superconductors using a uniaxially anisotropic pairing interaction, obtained by means of the linearized Gor'kov gap equation. In addition to the intrinsic anisotropy of the p-wave states, we also include effective mass anisotropies in our calculations. We investigate the $H_{c2}(T)$ phase diagrams for several combinations of anisotropy, leading to novel $H_{c2}(T)$ properties, including upward curvature. We discuss the relevance of our results to experiments on UCoGe.