The critical field for superfluid 3He in axially compressed, anisotropic silica aerogel is shown to be the result of an anisotropic distribution of magnetic impurities affecting the superfluid A phase. The critical field results from the fact that the A phase is suppressed relative to the B phase which is immune to the effects of magnetic impurities. In the absence of magnetic quasiparticle scattering in anisotropic aerogel, we find that the relative symmetry of A and B phase order parameters is the same as in isotropic aerogel, just as it is in pure superfluid 3He. These results are of potential importance for understanding unconventional superconductivity.
@article{arxiv.1908.01739,
title = {The Effect of Magnetic Impurities on Superfluid $^3$He in Aerogel},
author = {A. M. Zimmerman and M. D. Nguyen and J. W. Scott and W. P. Halperin},
journal= {arXiv preprint arXiv:1908.01739},
year = {2020}
}