Enhancement of Magnetization in Liquid ³He at Aerogel Interface

Abstract

A novel feature of condensate state in liquid ³He is predicted theoretically, which consists of spin triplet s-wave Cooper pairs (Higashitani et al. in J. Low. Temp. Phys. 155:83–97, 2009). Such a spin triplet s-wave state will appear inside aerogel near the surface boundary contacting with superfluid ³He-B, and the enhancement of magnetization due to s-wave state is theoretically expected (Nagato et al. in J. Phys. Soc. Jpn. 78:123603, 2009; Higashitani et al. in Phys. Rev. B 85:024524, 2012). In order to detect this proximity effect, we made the interface in columnar glass tube which coated with 2.5 layer ⁴He, and set a saddle shape NMR coil very near the interface. At 7 bar, we found that superfluidity in liquid ³He inside aerogel never occurred, even at considerably low temperatures. At 24 bar below T/T _c =0.392, we observed no decrease of magnetization with decreasing temperatures. This phenomenon might be due to spin triplet s-wave Cooper pairs.