EuTZn (T=Pd, Pt, Au) with TiNiSi-type structure—Magnetic properties and 151Eu Mössbauer spectroscopy

The europium compounds EuTZn (T=Pd, Pt, Au) were synthesized from the elements in sealed tantalum tubes in an induction furnace. These intermetallics crystallize with the orthorhombic TiNiSi-type structure, space group Pnma. The structures were investigated by X-ray diffraction on powders and single crystals: a=732.3(2), b=448.5(2), c=787.7(2) pm, R1/wR2=0.0400/0.0594, 565 F2 values for EuPdZn, a=727.8(3), b=443.7(1), c=781.7(3) pm, R1/wR2=0.0605/0.0866, 573 F2 values for EuPtZn, and a=747.4(2), b=465.8(2), c=789.1(4) pm, R1/wR2=0.0351/0.0590, 658 F2 values for EuAuZn, with 20 variables per refinement. Together the T and zinc atoms build up three-dimensional [TZn] networks with short T–Zn distances. The EuTZn compounds show Curie–Weiss behavior in the temperature range from 75 to 300 K with μeff=7.97(1), 7.70(1), and 7.94(1) μB/Eu atom and θP=18.6(1), 34.9(1), and 55.5(1) K for T=Pd, Pt, and Au, respectively, indicating divalent europium. Antiferromagntic ordering was detected at 15.1(3) K for EuPdZn and canted ferromagnetic ordering at 21.2(3) and 51.1(3) K for EuPtZn and EuAuZn. 151Eu Mössbauer spectroscopic measurements confirm the divalent nature of the europium atoms by isomer shift values ranging from −8.22(8) (EuPtZn) to −9.23(2) mm/s (EuAuZn). At 4.2 K full magnetic hyperfine field splitting is observed in all three compounds due to magnetic ordering of the europium magnetic moments.

Europium coordination in EuPdZn, EuPtZn, and EuAuZn.Figure optionsDownload as PowerPoint slide