Evolution of magnetism in LnCuGa3 (Ln = La–Nd, Sm–Gd) studied via μSR and specific heat

Abstract Muon spin rotation/relaxation (μSR) and specific heat measurements are presented for polycrystalline Ln CuGa 3 , with Ln  = La–Nd, and Sm–Gd. All materials undergo magnetic ordering transitions, apart from non-magnetic LaCuGa 3 , and PrCuGa 3 , which shows the onset of short range correlations below 3 K but no long-range magnetic order down to T  = 25 mK. While magnetic order in the Ce and Nd compounds is incommensurate with the lattice, the order is commensurate for the Sm and Eu compounds. The strong damping in GdCuGa 3 prevents us from determining the nature of magnetism in that system. SmCuGa 3 exhibits two precessional frequencies, which appear at different temperatures, suggesting inhomogeneous magnetic ordering or a second magnetic/structural phase transition.