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Dissipative Superfluid Mass Flux Through Solid 4he, Ye. Vekhov, Robert Hallock
Dissipative Superfluid Mass Flux Through Solid 4he, Ye. Vekhov, Robert Hallock
Robert Hallock
The thermomechanical effect in superfluid helium is used to create an initial chemical potential difference ∆u_0 across a solid 4_He sample. This ∆u_0 causes a flow of helium atoms from one reservoir filled with superfluid helium, through a sample cell filled with solid helium, to another superfluid-filled reservoir until potential equilibrium between the reservoirs is restored. The solid helium sample is separated from each of the reservoirs by Vycor rods that allow only the superfluid component to flow. With an improved technique, measurements of the flow F at several fixed solid helium temperatures T have been made as a function …
Universal Temperature Dependence, Flux Extinction And The Role Of 3he Impurities In Superfluid Mass Transport Through Solid 4he, Ye. Vekhov, W. J. Mullin, Robert B. Hallock
Universal Temperature Dependence, Flux Extinction And The Role Of 3he Impurities In Superfluid Mass Transport Through Solid 4he, Ye. Vekhov, W. J. Mullin, Robert B. Hallock
Robert Hallock
The mass flux, F, carried by as-grown solid 4_He in the range 25.6-26.3 bar rises with falling temperature, and at a concentration-dependent temperature, T_d, the flux decreases sharply within a few mK. We study F as a function of 3_He impurity concentration, χ. We find that T_(d )is an increasing function of increasing χ. At temperatures above T_d the flux has a universal temperature dependence and the flux terminates in a narrow window near a characteristic temperature T_h ≈ 625 mK, which is independent of χ.