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of γ = 6.0 mJ/molK $^{223}$, T$_{D}$ = 180 K 24 and figures of degeneration of the 4 phonon optical branches 2-5-3-5 $^{25}$, were taken. The remaining values were analyzed by testing all the free parameters in order to reach the best agreement with experimental data, based on the equation listed hereafter for the other specific heat contribution: 

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The value found for the Sommerfeld coefficient was γ = 7 mJ/mol K $^{$_{−}$2}$, which is a typical figure that may be expected and measured in Sm intermetallics compounds $^{23}$. We also analyzed the temperature evolution of the magnetic entropy (Fig.2). In the temperature range 1.8 - 20 K we observed a high jump up to the value Rln2 and we presume that the magnetic ground state of our compound is a doublet. An additional increase of temperature led to a gradual growth of magnetic entropy. The values for entropy should reach the value Rln6 when the energy of the third doublet is achieved, but unfortunately this doublet is above room temperature. We have measured specific heat data up to 400 K, but the data were strongly affected by the transformation of apiezon from temperatures over 250 K and it was inappropriate to solve the absolute value of entropy from the experimental data in this temperature range. 

A huge energy gap of 130 K was observed between the ground and the first excited state, respectively, which is in good agreement with the findings in 4 and our theoretical calculations. The existence of a third doublet, indicated to be around room temperature, motivated us to measure magnetization up to 400 K, because a strong influence of CF on the susceptibility behavior was expected, as will be discussed later. 

## AC susceptibility and magnetization 

The temperature dependence of the susceptibility measured in the AC magnetic field applied along the a - and c -axis, respectively, is shown in Fig.3. The a -axis data were characterized by a very low, nearly-temperature-independent signal free of any considerable anomaly exceeding signal noise, whereas the data measured in the AC field applied along the 

