Search

The novel composition – TiFe1.3Os3.9B2.8 – is the first quaternary phase of the NbRuB structure type. The layer‐like structure consists of boron (mixed with 8 % Fe) dumbbells in the same layer as osmium atoms, some sites with mixed occupancies. The second layer has isolated boron, osmium/titanium (51 % Os) and iron atoms. The presence of iron enables the study of magnetism as Fe‐chains are present, with intra‐ and interchain distances of 3.02 Å and 5.76 Å, respectively. Density functional theory (DFT) predicts magnetic ordering to be likely with the antiferromagnetic ground state only 13 meV more favorable than the ferromagnetic state. This discovery opens the possibilities of studying various quaternary compositions in the superconducting NbRuB structure type. [ABSTRACT FROM AUTHOR]

We present the first bulk synthesis of Ti3Co5B2, which was realized by arc-melting a Co-rich elemental mixture. Our X-ray diffraction studies revealed a Ti/Co mixed occupancy on one of two possible Ti sites suggesting a phase width with x = 0-0.52 in Ti3- xCo5+ xB2. Moreover, we studied experimentally and theoretically the isoelectronic substitution of Ti and Co by their respective higher homologues (Zr/Rh and Hf/Ir). Surprisingly, Ti3Co5B2-type phase was obtained only for the Hf/Ir combination (single crystal analysis of Hf3Ir5B2), whereas for Zr/Rh a perovskite-like phase (ZrRh3Bx) was discovered instead. We found that small but crucial differences (atomic radius ratio and electronegativity difference) between elements of the same group in the periodic Table are responsible for the unexpected trend deviation. This finding is supported by DFT calculations of the free energy of formation. [ABSTRACT FROM AUTHOR]