Related Experiment Video
Updated: Oct 23, 2025
12:20
Sputter Growth and Characterization of Metamagnetic B2-ordered FeRh Epilayers
Published on: October 5, 2013
14.8K
Subpicosecond metamagnetic phase transition in FeRh driven by non-equilibrium electron dynamics
Federico Pressacco1,2, Davide Sangalli3,4, Vojtěch Uhlíř5,6
1The Hamburg Centre for Ultrafast Imaging, Hamburg University, Hamburg, Germany. federico.pressacco@desy.de.
Nature Communications
|August 25, 2021
Summary
Ultrafast laser pulses can switch materials between magnetic states. This study reveals how light triggers a ferromagnetic phase in iron-rhodium (FeRh) within 350 femtoseconds via electronic band structure changes.
Area of Science:
- Condensed matter physics
- Ultrafast phenomena
- Magnetism
Background:
- Femtosecond light can induce phase transitions, tuning material properties on ultrafast timescales.
- First-order phase transitions often involve complex non-equilibrium states, hindering precursor detection.
Purpose of the Study:
- To elucidate the subpicosecond processes behind photoinduced ferromagnetic order in iron-rhodium (FeRh).
- To understand the role of electronic band structure modification in ultrafast phase transitions.
Main Methods:
- Time-resolved photoelectron spectroscopy.
- Ab-initio electron dynamics calculations.
Main Results:
- Photoexcitation modifies the electronic band structure, not just state occupation.
- Ferromagnetic order in FeRh is established 350 ± 30 fs after laser excitation.
- Ab-initio calculations suggest Rh-to-Fe charge transfer initiates the transition.
Conclusions:
- Light-induced changes in electronic band structure drive ultrafast phase transitions.
- Charge transfer plays a key role in generating ferromagnetic order in FeRh.
More Related Videos
Related Concept Videos
01:31Ferromagnetism
2.5K
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...
2.5K
01:23Atomic Nuclei: Nuclear Relaxation Processes
791
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.
791
01:30Paramagnetism
2.7K
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...
2.7K
01:12Fermi Level Dynamics
412
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...
412
01:27π Electron Effects on Chemical Shift: Overview
1.3K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.3K
01:05Atomic Nuclei: Magnetic Resonance
840
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...
840