Magnetic transitions in the 1D chain compounds NdPd₅Ge₃and NdPt₅Ge₃

We present the structural and initial magnetic characterization of the previously unreported materials NdPd₅Ge₃and NdPd₅Ge₃. These materials, with one-dimensional Nd chains, crystallize in the orthorhombic YNi₅Si₃-type structure in space groupPnma. Magnetic ordering is observed for both compounds at ∼2.2 K for NdPd₅Ge₃and ∼3.0 K for NdPt₅Ge₃. A magnetic-field-induced transition is clearly observed for NdPd₅Ge₃below 2 K, at an applied magnetic field of around 1.6 T. The heat capacity data reveals that essentially all the available magnetic entropy is released at the magnetic ordering transition for NdPd₅Ge₃but that only 29% is seen for NdPt₅Ge₃at temperatures down to 1.5 K, the data implying that a second magnetic transition can be expected at lower temperatures.