Anomalous behavior of the low-temperature magnetic specific heat of NiCl2 2H2O

The specific heat of NiCl2 2H2O has been measured for 1.2 K<T<24. 5 K. Two peaks are observed, at T1c=6. 309 K and at T2c=7. 258 K. The former can be described by a power law Cmag|T-T1c|-0. 3. The T2c peak is asymmetric and displays power-law behavior with smaller exponents. Below 4K, CpT, but the line does not extrapolate to zero at T=0. The conventional explanations for some previously observed double transitions in other substances do not seem to be applicable to NiCl2 2H2O, thus raising intriguing questions as to the origin of the double Cp peaks. Two possible explanations are sketched.