Magnetic properties of CePt3Al5 single crystal

CePt$_3$Al$_5$ crystalizes in the orthorhombic type of structure with the space group \textit{Pnma} (\#62). Ce atoms are well separated in their unit cell, making 1D chains of Ce magnetic ions along the \textit{b}-axis with the interchain distance of about 6 {\AA}. Magnetic properties of isostructural site-exchange variant analogs such as CePd$_5$Ge$_3$ and CePt$_5$Ge$_3$ were intensively studied to clarify their low dimensional magnetic behaviors. We succeeded in growing single crystals by means of the Czochralski method in a tetra-arc furnace. To investigate the electronic ground state of CePt$_3$Al$_5$, we measured the physical properties such as heat capacity, electrical resistivity, and magnetic properties using a commercial Physical Property Measurement System (PPMS) and Magnetic Property Measurement System (MPMS). Low-temperature magnetic properties was also measured a capacitive Faraday force magnetometer down to 0.5 K, using $^3$He refrigerator.
The temperature dependence of specific heat of CePt$_3$Al$_5$ in form of \textit{C/T} shows two features. A clear $\lambda$-type anomaly owing to an antiferromagnetic order, inferred from magnetic susceptibility measurement, is observed at T$_N$ = 1.1 K. Moreover, at T$_m$ = 0.8 K, a sharp peak is exhibited, indicating the occurrence of the first-order phase transition below T$_N$. The transition at T$_m$ is accompanied by prominent hysteresis behaviors with respect to the temperature in the electrical resistivity and magnetic susceptibility. Detailed bulk properties measurements allow us to construct a magnetic field – temperature (\textit{B-T}) magnetic phase diagram of CePt$_3$Al$_5$. The ground state of this compound is, most probably, an uncompensated or canted-antiferromagnetic state with a spontaneous magnetic moment.