Magnetism of CePt2Sn2

CePt2Sn2 has the tetragonal P4/nmm structure. Polycrystalline (pcr) material possesses in addition a small mono-clinic distortion and shows a magnetic transition below 1K, while no such transition is seen in purely tetragonal single-crystalline (scr) samples. Our μSR, specific heat and magnetization data are consistent with a spin-glass-like (sgl) state below 0.45K in scr and long-range order (lro) below 0.85K in pcr samples. μSR demonstrates clearly that the Ce3+ spin ensemble remains dynamic down to lowest temperatures (0.02K) in the sgl state, but reaches the usual quasi–static limit in the lro state. These results are discussed in terms of geometrical magnetic frustration.