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A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti1+xRh2−x+yIr3−yB3 structure type, space group Pbam (no. 55) with the lattice parameters a = 8.655(2), b = 15.020(2), and c = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti1+xRh2−x+yIr3−yB3-type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B4 units than to isolated boron atoms. [ABSTRACT FROM AUTHOR]

Metal‐rich borides with the Ti3Co5B2‐type structure represent an ideal playground for tuning magnetic interactions through chemical substitutions. In this work, density functional theory (DFT) and experimental studies of Ru‐rich quaternary borides with the general composition A2MRu5B2 (A=Zr, Hf, M=Fe, Mn) are presented. Total energy calculations show that the phases Zr2FeRu5B2 and Hf2FeRu5B2 prefer ground states with strong antiferromagnetic (AFM) interactions between ferromagnetic (FM) M‐chains. Manganese substitution for iron lowers these antiferromagnetic interchain interactions dramatically and creates a strong competition between FM and AFM states with a slight preference for AFM in Zr2MnRu5B2 and for FM in Hf2MnRu5B2. Magnetic property measurements show a field dependence of the AFM transition (TN): TN is found at 0.1 T for all phases with predicted AFM states whereas for the predicted FM phase it is found at a much lower magnetic field (0.005 T). Furthermore, TN is lowest for a Hf‐based phase (20 K) and highest for a Zr‐based one (28 K), in accordance with DFT predictions of weaker AFM interactions in the Hf‐based phases. Interestingly, the AFM transitions vanish in all compounds at higher fields (>1 T) in favor of FM transitions, indicating metamagnetic behaviors for these Ru‐rich phases. [ABSTRACT FROM AUTHOR]

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]