Thermal conductivity of solid ammonia at low temperatures

Abstract

The results of measurements of the thermal conductivity dependence on temperature of pure ammonia crystal obtained in the temperature range 1.3–44 K have been shown. Quantitatively, the sample displays the thermal conductivity typical for a dielectric crystal. Below 2 K a singularity of the dependence of thermal conductivity coefficient on temperature was observed. The singularity was linked to the existence of TLS in the crystal. The analysis of the temperature dependence of the phonon mean free path in the NH3 crystal was also done.

1I/‘Oumuamua as an N2 Ice Fragment of an exo‐Pluto Surface: I. Size and Compositional Constraints

“…Luna et al (2014) as an outlier therein, heat capacity, thermal conductivity at 30 K, β phase spectrum at 50cm −1 . 1, Silvera (1980); 2, Souers (1986), at 4.2 K; 3, Huebler and Bohn (1978), at 6 K; 4, Sandford and Allamandola (1993a); 5, Shakeel et al (2018), and references therein; 6, Hwang et al (2005); 7, Fenichel and Serin (1966), at 9 K; 8, Weston and Daniels (1984), at 9 K; 9, Gupta (1969); 10, Frels et al (1974);11, Öberg et al (2005); 12, Bisschop et al (2006);13, Collings et al (2015); 14, Fayolle et al (2016);15, Lipiński et al (2007);16, Trowbridge et al (2016), at 30 K;17, Cook and Davey (1976), at 30 K;18, Stachowiak et al (1994), at 30 K;19, Luna et al (2014), and references therein;20, Bierhals (2001); 21, Clayton and Giauque (1932);22, Stachowiak et al (1998); 23, Sandford and Allamandola (1988);24, Szmyrka-Grzebyk et al (1998);25, Freiman and Jodl (2004), and references;26, Bier and Jodl (1984), from peak in Raman; 27, Ramsey (1963); 28, Vogt and Pitzer (1976), at 21 K;29, Jeżowski et al (1997), at 20 K;30, Orbriot et al (1978), from peak in Raman; 31, Giauque and Egan (1937), heat capacity at 82 K; 32, Sandford and Allamandola (1990);33, Blum (1975); 34, Overstreet and Giauque (1937); 35, Romanova et al (2013); 36, Sandford and Allamandola (1993b); 37, Giauque and Stout (1936);…”