Thermal properties of U 3 Al 2 Si 3 single crystal

• Published in: physica status solidi (b) Vol. 243; no. 1; pp. 304 - 308
• Main Authors: Mihalik, Marián, Flachbart, Karol, Gabáni, Slavomír, Maťaš, Slavomír, Mihalik, Matúš, Rogl, Peter, Troć, Robert
• Format: Journal Article
• Language: English
• Published: 01-01-2006
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200562433

Heat capacity data of U
3
Al
2
Si
3
single crystal exhibit a maximum at 38 K connected with a transition to a magnetically ordered state. For a full description of the electron part we used
γ
0
= 145 mJ/mol K
2
and for the phonon part of the specific heat we used the harmonic approximation of the phonon spectrum including both the Debye model with
T
D
= 296 K and the Einstein model with
T
E
= 136, 249 and 438 K. The heat capacity data below the magnetic transition down to 2 K fit very well within the model introducing the energy gap
Δ
= 39 K in the dispersion relation of magnons. An upturn of the
C
/
T
(
T
) curve, found below
T
= 2 K, can not be fully attributed to the nuclear Schottky contribution. The electronic heat capacity coefficient (
γ
≈ 230 mJ/mol K
2
is enhanced and varies between 0.15 K and 12 K as the square root of
T
. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)