Related Experiment Video
Updated: May 23, 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
Magnetization reversal process at atomic scale in systems with itinerant electrons.
1Department of Physics, St-Petersburg State University, Ul'yanovskaya ulitsa 1, Petrodvorets, St Petersburg 198504, Russia. v_uzdin@mail.ru
Summary
This study investigates the magnetic response of electron systems to magnetic fields, revealing how electron configuration influences magnetic moments in materials like iron and chromium. Findings are crucial for understanding and designing magnetic materials and devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Investigating the magnetic response of itinerant electron systems is crucial for understanding magnetism in materials.
- Microscopic Hamiltonians provide a fundamental basis for determining spin-polarized electronic structures.
Purpose of the Study:
- To investigate the magnetic response of itinerant electron systems to external magnetic fields.
- To calculate magnetic moments and thermodynamic potentials as a function of moment orientation.
- To explore magnetization reversal processes in exchange spring magnets.
Main Methods:
- Utilizing a microscopic Hamiltonian to determine spin-polarized electronic structure.
- Calculating magnetic moments and grand thermodynamic potential for d-electronic subsystems.
- Modeling magnetization reversal using a slab of Fe as a soft magnetic layer and an external interface field.
Main Results:
- Self-consistent magnetic solutions are highly dependent on d-electron number and Fermi energy.
- Two branches of magnetic solutions (high and low magnetic moments) were found for parameters matching alpha-Fe.
- Only low-spin solutions were observed for bulk Cr, Fe impurities in Cr, and Cr impurities in Fe.
- Hysteresis loop dependence on Fe slab thickness and interface field was investigated for exchange spring magnets.
Conclusions:
- The d-electron number and its position relative to the Fermi energy are critical for self-consistent magnetic solutions.
- Material-specific magnetic behaviors (e.g., high/low spin states) are predicted based on electronic structure.
- The developed theory can describe magnetization reversal in exchange spring magnets, with implications for magnetic device design.
Related Concept Videos
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:05Atomic Nuclei: Magnetic Resonance
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
01:31Ferromagnetism
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...
01:26Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
01:30Paramagnetism
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...