Effect of Magnetic Scattering on Superfluid Transition of 3He in Nematic Aerogel

We present results of high magnetic field experiments in pure ${}^3$He (in the absence of ${}^4$He coverage) in nematic aerogel. In this case the aerogel strands are covered with few atomic layers of solid paramagnetic ${}^3$He, which enables the spin-exchange mechanism for ${}^3$He quasiparticles scattering. Our earlier NMR experiments showed that in low fields, instead of the polar phase, the A phase is expected to emerge in nematic aerogel. We use a vibrating wire resonator with the sample of aerogel attached to it and measure temperature dependencies of resonance properties of the resonator at different magnetic fields. A superfluid transition temperature of ${}^3$He in aerogel, obtained from the experiments, increases nonlinearly in applied magnetic field. And this increase is suppressed compared with that for bulk A${}_1$ phase, which we attribute to an influence of the magnetic scattering channel, previously considered theoretically for the case of ${}^3$He confined in isotropic silica aerogel. However, we observe the essential quantitative mismatch with theoretical expectations.