Structural Determinants in the Higher Borides

Effect of electron-phonon coupling on the superconducting transition temperature in dodecaboride superconductors: A comparison ofLuB12withZrB12Teyssier1, Lortz2, Petrović3 et al. 2008Phys. Rev. B464410View full textAdd to dashboardCite

“…LuB 12 crystallizes in the UB 12 type structure work 23 which can be viewed as a cubic rocksalt arrangement of Lu and B 12 cuboctahedral clusters. The sample preparation process involves synthesising dodecaborides by a borothermal reduction of the metal oxides in vacuum at 1900 K, compacting these powders into rods and subsequently sintering them, then finally inductive zone melting in a high frequency induction zone unit 24 .…”

Thermodynamically-consistent derivation and computation of twinning and fracture in brittle materials by means of phase-field approaches in the finite element method

“…As a result of possessing hardness above 30 GPa, low mass density (2.52 g ∕cm 3 ), and high Hugoniot elastic limit (17-20 GPa), boron carbide (B 4 C) has received considerable attention in ballistic applications (Karandikar et al, 2009). Due to its high melting point and thermal stability (Matkovich et al, 1977), favorable abrasion resistance (Subramanian et al, 2010), and high temperature semiconductivity (Thevenot, 1990), boron carbide excels in refractory, nuclear, and novel electronic applications, respectively; however, its performance is hindered by one or more of a number of inelastic deformation mechanisms, including deformation twinning (Li et al, 2010), stressinduced phase transformations (An et al, 2014;Eremeyev and Fischer, 2010), and various fracture behaviors (An and Goddard III, 2015) when subjected to mechanical stresses exceeding their elastic limit. The key failure mechanisms in boron carbide (e.g., cleavage fracture and twinning) are commonly studied experimentally using numerous characterization techniques (e.g., transmission electron microscopy (Zhao et al, 2016) and Raman spectroscopy (Yan et al, 2009)).…”

Crystal structures of dodecaborides: complexity in simplicity

“…The cubic structure of YB 12 was later confirmed on single crystals [5], but a single crystal of ScB 12 studied in the same work [5] was determined as tetragonal I4/mmm, with unit-cell parameters a tet ≈ 5.22 Å, c tet ≈ 7.35 Å that could be transformed to pseudo-cubic: a = b = a tet √ 2 ≈ 7.38 Å, c = c tet ≈ 7.35 Å. All the above findings were summarized in a review article [6]. A more recent review [7], which was mainly devoted to magnetic, superconducting, and other physical properties of rare-earth dodecaborides, began by describing the dodecaboride structure and by presenting structural information on RB 12 with R = Tb -Lu from the second half of the lanthanide series supplemented with YB 12 and ZrB 12 .…”