High-pressure synthesis and crystal structure of a novel intermetallic compound Mn(Al,Ge)5

Abstract

A novel intermetallic compound of the Mn–Al–Ge system, Mn(Al,Ge)5, was synthesized under high pressure and high temperature (5 GPa and 600 °C). The crystal structure was tetragonal with a space group of I4/mcm (no. 140), which was isostructural with PdGa5 or FeAl3Si2. The crystallographic parameters were refined by Rietveld analysis from powder X-ray diffraction data, yielding a = 0.624026 (5) nm, c = 0.981858 (10) nm, and Z = 4. The structure could be considered a defect-Cr5B3 (D8l) structure. The hysteresis loop and magnetization–temperature curve revealed the synthesized Mn(Al,Ge)5 to be paramagnetic: the long Mn–Mn distance led to a structure without magnetic ordering.