High-quality single crystals of R3Al11 (R = La, Ce, Pr, and Nd) with the La3Al11-type orthorhombic crystal structure (space group Immm) have been grown by the Al-flux method. For Ce 3Al11, signatures for ferromagnetic and antiferromagnetic orderings at TC = 6.3 K and TN = 3.2 K, respectively, have been observed in the magnetic susceptibility, magnetization, specific heat, and electrical resistivity. An antiferromagnet Pr3Al11, on the other hand, exhibits two magnetic transitions at TN1 = 12.6 K and TN2 = 3.1 K. An antiferromagnet Nd3Al11 also exhibits multiple magnetic transitions at TN1 = 13.2 K, T N2 = 9.4 K, TN3 = 2.9 K, and TN4 = 1.77 K in zero magnetic field. The transition at TN4 has a first-order character. The crystalline electric field (CEF) analysis of magnetic susceptibility, magnetization and specific heat data shows that the CEF splitting is larger for Ce3Al11 than for Pr 3Al11 and Nd3Al11. The CEF ground state of Pr3Al11 is a singlet. Magnetic order occurs in this compound owing to the exchange mixing of the CEF ground state and low-lying excited states. The ferromagnetic like component of the magnetization for H ∥  is characteristic of R3Al11 (R = Ce, Pr, and Nd), which is most likely due to the Dzialoshinsky-Moriya interaction for two nonequivalent R atoms.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)