Seminarium Oddziału Badań Magnetyków

Magnetic ordering in uranium germanides UT_1-xGe₂ (T = Fe, Ni, Os)

dr Maria Szlawska

In my talk, I will present results of our recent studies of three uranium-based phases with composition UT_1-xGe₂ (for T = Fe, Ni, Os). They were synthesized and characterized in the course of systematic search for novel uranium-based germanides.

Our investigations confirmed that these phases possess UFe_0.45Ge₂, UNi_0.45Ge₂ and UOs_0.25Ge₂ compositions and crystallize with orthorhombic unit cell of CeNiSi₂-type (for T = Fe, Ni) and monoclinic unit cell of URu_0.29Ge₂-type (for T = Os). The physical properties measurements revealed that UFe_0.45Ge₂ is a cluster-glass system with the freezing temperature of 37 K, UNi_0.45Ge₂ show long-range antiferromagnetic ordering below 47 K, and UOs_0.25Ge₂ orders ferromagnetically at 54 K. Furthermore, the Ni-bearing phase undergoes metamagnetic transition in high magnetic fields.