Related Experiment Videos
Structural phase transitions of HfV2 at low temperatures
Y Zhao1, F Chu, R B Von Dreele
1LANSCE Division, Los Alamos National Laboratory, NM 87545, USA. yzhao@lanl.gov
Acta Crystallographica. Section B, Structural Science
|August 16, 2000
Summary
This study reveals the sequential structural phase transitions in hafnium divanadium (HfV2) at low temperatures. Using X-ray diffraction, researchers observed transitions from cubic to tetragonal, then to orthorhombic phases, detailing lattice changes.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Crystallography
Background:
- Hafnium divanadium (HfV2) is a Laves phase compound known for its interesting physical properties.
- Understanding its structural behavior at low temperatures is crucial for potential applications.
Purpose of the Study:
- To investigate the low-temperature structural phase transitions of HfV2.
- To characterize the crystallographic changes and atomic rearrangements during these transitions.
Main Methods:
- High-resolution synchrotron X-ray powder diffraction.
- Rietveld refinement for structural analysis.
Main Results:
- Observed a complete sequence of phase transitions: cubic (Fd3m) to tetragonal (I4(1)/amd) at 112 K, then to orthorhombic (Imma) at 102 K.
- Detailed lattice parameters and atomic positions for each phase.
- Identified peak splitting and extra diffraction peaks indicating lattice distortion in low-symmetry phases.
- Observed abnormal thermal contraction in tetragonal and orthorhombic phases.
Conclusions:
- HfV2 undergoes distinct structural transformations upon cooling.
- The observed transitions are significant, marked by lattice distortions and thermal contraction.
- Rietveld refinement successfully determined structural parameters for the low-temperature phases.