Hidden low-temperature instability in PrOs4Sb12

作者：Grube K^*; Zaum S; Bauer E D; Maple M B; v Loehneysen H

来源：Physica Status Solidi B-Basic Solid State Physics, 2010, 247(3): 571-573.

DOI：10.1002/pssb.200983070

The low-temperature behavior of many correlated electron systems is characterized by the appearance of macroscopically ordered states that show a dome-shaped evolution of their transition temperatures as a function of non-thermal control parameters. In the heavy-fermion compound PrOs4Sb12, a field-induced phase emerges in a magnetic field range between B approximate to 4.5 and 13.5 T. The phase is characterized by antiferroquadrupolar (AFQ) ordering of the Pr3+ ions. We measured the specific heat of PrOs4Sb12 single crystals in magnetic fields up to B = 14 T parallel to the crystallographic [100] direction to determine the entropy S as a function of T and B. Above the maximum AFQ transition temperature, the entropy S(T = const, B) reveals a pronounced maximum. We show that this maximum can be related to a low-temperature instability which is produced by the degeneracy of the lowest crystalline electric field (CEF) energy levels.

• 出版日期2010-3