Related Experiment Video
Updated: May 4, 2026
09:06
Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
6.6K
Fe-vacancy order and superconductivity in tetragonal β-Fe1-xSe.
Ta-Kun Chen1, Chung-Chieh Chang, Hsian-Hong Chang
1Institute of Physics, Academia Sinica, Taipei 115, Taiwan.
Summary
Iron vacancies and magnetic ordering are present in nonintercalated iron selenide (FeSe) superconductors. This finding suggests these features are crucial for understanding FeSe-based superconducting systems.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid State Chemistry
Background:
- Superconductivity in intercalated FeSe systems (A1-xFe2-ySe2) shows transition temperatures between 30-46 K.
- The exact superconducting phases and parent phases in these systems are still under investigation, with magnetic phases involving iron and potassium vacancies identified.
Purpose of the Study:
- To investigate the presence and ordering of iron vacancies in nonintercalated FeSe (PbO-type tetragonal β-Fe1-xSe).
- To determine the relationship between iron vacancy ordering, magnetic properties, and superconductivity in FeSe.
Main Methods:
- Analytical electron microscopy was employed to identify and characterize iron vacancy ordering.
- Magnetic and structural characterization was performed to understand the low-temperature properties of the identified phases.
Main Results:
- Three distinct types of iron vacancy ordering were discovered in β-Fe1-xSe.
- One identified iron-vacancy ordered phase was found to be non-superconducting and magnetic at low temperatures.
Conclusions:
- The findings indicate that iron vacancy ordering and associated magnetic phases are not exclusive to intercalated FeSe systems.
- Magnetic β-Fe1-xSe phases with specific iron vacancy orders are proposed as the likely parent phases for FeSe superconductors, challenging previous assignments.
Related Concept Videos
01:31Ferromagnetism
2.8K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.8K
01:28Types Of Superconductors
1.7K
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
1.7K
01:24Superconductor
1.9K
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
1.9K
01:12Fermi Level Dynamics
1.1K
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
1.1K
01:18Fermi Level
2.6K
The Fermi-Dirac function is represented by an S-shaped curve indicating the probability of an energy state being occupied by an electron at a given temperature. The Fermi level is the energy level at which there is a fifty percent chance of finding an electron, and it is positioned between the lower-energy valence band and the higher-energy conduction band.
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
2.6K
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
143
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
143