Anisotropy of the Propagation of Sound in the <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi></math></span> Phase of Superfluid <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">He</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>3</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow></math></span>

Pat R. Roach; B. M. Abraham; P. D. Roach; J. B. Ketterson

doi:10.1103/PhysRevLett.34.715

Anisotropy of the Propagation of Sound in the $A$ Phase of Superfluid ${}^{3}{He}$

Pat R. Roach, B. M. Abraham, P. D. Roach, and J. B. Ketterson

Phys. Rev. Lett. 34, 715 – Published 24 March 1975

Abstract

We have studied the temperature dependence of the anisotropy of the attenuation and velocity shift of 20-MHz ultrasound propagating in the $A$ phase of ${}^{3}{He}$ at pressure of 26 bar and for magnetic fields less than 27 G. Measurements in the $B$ phase at 21.0 bar show no anisotropy.