Related Experiment Video
Updated: May 22, 2026
04:51
Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride
Published on: July 8, 2021
4He crystals in superfluid under zero gravity.
Takuya Takahashi1, Ryuji Nomura, Yuichi Okuda
1Department of Physics, Tokyo Institute of Technology, Tokyo, Japan.
Summary
Superfluid helium-4 (4He) crystals visually adapted their shape in microgravity. Lower temperatures revealed significant changes in crystal facets, demonstrating growth under zero gravity conditions.
Area of Science:
- Condensed Matter Physics
- Low-Temperature Physics
- Materials Science
Background:
- Understanding crystal growth and morphology under varying gravitational conditions is crucial for materials science.
- Superfluid helium-4 (4He) provides a unique system for studying fundamental physical phenomena due to its quantum properties.
Purpose of the Study:
- To investigate the visual response of superfluid 4He crystals to rapid gravity reduction to near-zero levels.
- To observe changes in crystal shape and behavior during parabolic flights in a microgravity environment.
Main Methods:
- Visual observation of 4He crystals within a superfluid environment during parabolic flights.
- Experiments conducted at different temperatures (1.6 K and 0.63 K) to assess crystallization rates.
- Utilized acoustic wave pulses to momentarily detach crystals from the sample cell wall.
Main Results:
- At 1.6 K, 4He crystals in the body-centered cubic (bcc) phase showed no significant shape change due to low crystallization rates.
- At 0.63 K, 4He crystals in the hexagonal close-packed (hcp) phase exhibited significant shape changes, forming enlarged c facets and emerging a facets under zero gravity.
- Crystals remained attached to the wall due to adhesive forces from partial wetting; some detached crystals floated briefly before reattachment.
Conclusions:
- The crystallization rate significantly influences the observable response of 4He crystals to microgravity.
- Superfluid 4He crystals can achieve a quasi-equilibrium shape under zero gravity, with facet development dependent on temperature and phase.
- Adhesive forces play a critical role in anchoring crystals to surfaces even in a superfluid state.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
01:27Symmetry Elements in a Crystal
Crystal symmetry operations are isometric transformations that map objects onto indistinguishable copies while preserving distances, angles, and volumes. The simplest symmetry operation is translation, which shifts the entire infinite crystal lattice parallelly by a translation vector.Crystallographic rotations involve rotations by an angle of 2π/n around an axis without changing the positions of points on the axis. It is called the rotational axis of the symmetry, denoted by n. The combination...
01:24The Seven Crystal Systems: Overview
Crystals with various point group symmetries belong to different crystal classes, which are synonymous terms. Despite being in the same class, crystals may have distinct shapes, like cubes and octahedra. There are 32 three-dimensional point groups, all of which are systematically divided into seven crystal systems.The basic cubic crystal system, exemplified by NaCl, features orthogonal vectors (α = β = �� = 90°) of equal lengths (a = b = c). When specific requirements are not imposed on the...
02:54Molecular and Ionic Solids
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
01:29Liquid–Solid Solutions
The process of a solid dissolving in a liquid to form a solution is governed by the solubility limit, which is the maximum amount of the solid substance, or solute, that can be dissolved in a specific volume of the liquid or solvent. As the solute dissolves, it reaches a point where no more solute can be dissolved at a given temperature - this is known as the saturation point. However, if further solute is added and it manages to dissolve, the solution becomes supersaturated. Supersaturated...
01:19Crystal Density
The crystal lattice structure of a material allows us to determine how many molecules exist in its unit cell. With this information, alongside the unit-cell parameters - three distance parameters (a, b, c) and three angular parameters (α, β, γ).Density (ρ) = (Z × M) / (a × b × c × NA)where:Z is the number of formula units per unit cellM is the molar mass of the substancea, b, and c are the edge lengths of the unit cellNA is Avogadro’s numberFor a simple cubic lattice, atoms are located only at...