Magnetic properties of hexagonal PrAlGa

The magnetic properties of the hexagonal PrAlGa compound are presented. Polycrystalline samples were used for heat capacity and neutron diffraction studies, and a single crystal for the magnetization measurements. The main results are as follows: (i) below TN=5.0 K the magnetic structure is likely sine-wave-modulated with a propagation vector Q=(0.178, 0, 0); (ii) the magnetization is perpendicular to the c-axis; (iii) below TN along the [100] and [120] directions, smooth two-step metamagnetic behaviours are observed; and (iv) the crystalline electric field ground state is a non-magnetic singlet with also a singlet as the first excited state around 7 K. (orig.)