A₁-A₂ splitting in pure ³He in nematic aerogel

Here, we present the results of vibrating wire experiments in pure ³He (without ⁴He coverage) in nematic aerogel. We investigated the dependence of splitting of the superfluid transition temperature of ³He in aerogel on magnetic field. In addition to our previous work, we used a wider range of magnetic fields (up to 31 kOe) and managed to detect both the “upper” and “lower” superfluid transition temperatures. The solid paramagnetic ³He layer on the aerogel strands activates the magnetic scattering channel. According to theory, it should result in linear splitting at high (≥ 20 kOe) fields, while at lower fields the splitting is expected to be nonlinear. We were able to observe this nonlinearity, but we have a discrepancy with theoretical predictions regarding the range of fields where nonlinearity occurs. Possible reasons for this are discussed.