Magnetic properties of SEPtX-compounds (SE = rare earth element, X = P, As)

The magnetic properties of SEPtP and SEPtAs (SE = Sm, Gd, Tb, Tm, Yb, Lu) in the temperature range between 4 and 300 K were measured. The compounds crystallize in a modified AlB2-type structure (phosphides) and a related type, respectively. GdPtAs and TbPtP show at low temperatures ferromagnetic behaviour, SmPtAs and GdPtP are antiferromagnetic. At temperatures below 10 K TmPtP and TmPtAs are converted into a magnetic order too. Paramagnetism is observed in the cases of LuPtP and LuPtAs (Pauli-Paramagnetism) and SmPtP (temperature-independent Paramagnetism). YbPtP and YbPtAs follow the law of Curie-Weiss, the arsenide is one of the phases with dynamic intermediate valency. (author)