Normal-state and superconducting properties of HfV2

Ab Initio Calculations for Properties of Laves Phase V2m (M = Zr, Hf, Ta) Compounds

“…The results for lattice parameters a are reported in Table. 1. and compared with experimental and previous theoretical calculations. Our calculated value for lattice parameter a of V 2 Hf compound agrees well with that of the experimental value of 7.38 Å [3] and the theory work 7.34, 7.31 and 7.22 for V 2 Zr, V 2 Hf and V 2 Ta compounds respectively [4]. The relative deviation may be attributed to the fact that our calculation corresponds to the perfect bulk material at zero temperature, whereas the experimental sample was synthesized at high temperature (1550°C).…”

“…V 2 Zr, V 2 Hf and V 2 Ta have superconducting transition temperatures of 8K, 9K and 4K respectively, and a martensitic phase transition around 120 K [2]. B. Lüthi et al [3] present experimental results for the low-temperature specific heat, electrical resistivity, elastic constants, ultrasonic attenuation and thermal conductivity of the C15 Laves phases V 2 Hf. C-W. Zhang [4] studied theoretically the electronic structure and bonding properties for Lavesphase RV 2 (R= Ti, Nb, Hf, and Ta) compounds, using the full-potential linearized augmented plane-wave method (FLAPW) with the local density approximation (LDA).…”

Acoustic investigations of the ZrV2–H system

“…Acoustic investigations of structural transformations in the ZrV 2 system were carried out earlier [8][9][10]. It was supposed that this phase transition caused by softening of lattice modes was observed at a wide temperature range, beginning from the melting temperature [9].…”

A Proposal for a Composite with Temperature-Independent Thermophysical Properties: HfV2–HfV2O7

“…where B i , α i , and φ i denote the bulk modulus, coefficient of thermal expansion, and volume fraction, respectively, of component i [65]. The bulk modulus and the coefficient of thermal expansion of HfV 2 (HfV 2 O 7 ) of 117 GPa [32] (56 GPa [49]) and 9.9 × 10 −6 K −1 [36] (−7.2 × 10 −6 K −1 [40]), respectively, were used for the calculation of α c . The resulting volume fraction dependent expansion coefficient α c and averaged TCE of HfV 2 -HfV 2 O 7 composite are plotted in Figure 1.…”

“…Consequently, their thermoelastic anomaly is highly directionally dependent, but an isotropic temperature-independent behavior is desired for the proposed composite. Intermetallic cubic HfV 2 (space group: Fm-3m), which is stable from around 112 K up to the melting point of 1820 K [32,33], exhibits increasing thermoelastic constants in all probed directions [32] so that an increase in the macroscopic elastic modulus (E) upon heating was measured in polycrystalline samples [34,35]. Thus, HfV 2 is an ideal constituent to aim for a temperature-invariant elastic behavior in a composite.…”