The melting pressure and pressure in the liquid at a constant density of ultrapure 4He (0.3 ppb of 3He impurities) have been measured with an accuracy of about 0.5 μbar in the temperature range from 10 to 320 mK. The measurements show that the anomaly on the melting curve below 80 mK, which was recently observed [I. A. Todoshchenko et al., Phys. Rev. Lett. 97, 165302 (2006)], is entirely due to an anomaly in the elastic modulus of Be-Cu from which our pressure gauge is made. Thus, the melting pressure of 4He follows the T4 law due to phonons in the whole temperature range from 10 to 320 mK without any attribute of a supersolid transition.
Soviet Journal of Experimental and Theoretical Physics Letters
- Pub Date:
- July 2007
- Condensed Matter - Other Condensed Matter
- Published in JETP Letters, vol. 85, issue 9, page 555-558 (2007)