Intermetallic disordered magnetGd2Pt1.1Ge2.9and its relation to otherAlB2-type compounds

The intermetallic germanide ${\mathrm{Gd}}₂{\mathrm{Pt}}_1.1{\mathrm{Ge}}_2.9$ was synthesized using an arc-melting method. The crystal structure was characterized using powder x-ray diffraction, revealing a disordered ternary ${\mathrm{AlB}}₂$-type structure (space group $P6/mmm$, No. 191) with lattice parameters $a=4.2092(1)\phantom{\rule{0.16em}{0ex}}\AA{}$ and $c=4.0546(2)\phantom{\rule{0.16em}{0ex}}\AA{}$. Physical properties were investigated by magnetic susceptibility and heat capacity measurements, which indicated onset of antiferromagnetic order at ${T}_t=8\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The obtained properties were compared with the ones reported for other members of the ${\mathrm{AlB}}₂$-type ${\mathrm{Gd}}₂T{\mathrm{Ge}}₃$ ($T=\mathrm{Ni}$, Cu, and Pd) family. The magnetic ordering in these compounds was discussed in terms of their crystal structure and the influence of Gd ions.