MAGNETIC-PROPERTIES OF HEXAGONAL PRALGA

The magnetic properties of the hexagonal PrAlGa compound are presented . Polycrystalline samples were used for heat capacity and neutron diff raction studies, and a single crystal for the magnetization measuremen ts. The main results are as follows: (i) below T-N = 5.0 K the magneti c 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 T-N along the [100] and [120] directions, smooth two-ste p metamagnetic behaviours are observed; and (iv) the crystalline elect ric field ground state is a non-magnetic singlet with also a singlet a s the first excited state around 7 K.