We report results of experiments with superfluid ${}^3\mathrm{He}$ confined in aerogels with parallel strands which lead to anisotropic scattering of ${}^3\mathrm{He}$ quasiparticles. We vary boundary conditions for the scattering by covering the strands with different numbers of atomic ${}^4\mathrm{He}$ layers and observe that the superfluid phase diagram and the nature of superfluid phases strongly depend on the coverage. We assume the main reason for these phenomena is a magnetic channel of the scattering which becomes important at low coverages and can be essential in other Fermi systems with triplet pairing.

• Received 27 September 2017
• Revised 19 December 2017

DOI:https://doi.org/10.1103/PhysRevLett.120.075301