Effect of Global Anisotropy on Superfluid $^{3}$He in Compressed Aerogels

The importance of anisotropic scattering on the superfluid phases of $^{3}$He has been addressed recently and experiments using uniaxially distorted aerogel have been proposed in order to elucidate the influence of global anisotropy on the A-B transition $\footnote{C. L. Vicente {\it et al.}, Phys. Rev. B 72 094519 (2005).}$$^{,}$$\footnote{Kazushi Aoyama and Ryusuke Ikeda, Phys. Rev. B 73, 060504(R) (2006).}$. We performed high frequency transverse acoustic impedance measurements on superfluid $^{3}$He confined in 98{\%} porosity aerogel at 29 bar. The aerogel cylinder is compressed along the symmetry axis to generate global anisotropy. With 10{\%} axial compression, our measurements reveal that the A-like to B-like transition is absent on cooling down to $\approx $300 $\mu $K in the absence of magnetic field and in magnetic fields up to 3 kG. This behavior is in contrast to that in uncompressed aerogels, in which the supercooled A-like to B-like transitions have been identified by various experimental techniques. Our results are consistent with the theoretical prediction by Aoyama and Ikeda.