What is spin wave theory?
The basic assumption of the spin wave theory is that we can select a classical ground state and determine fluctuations around it. The spin waves dispersions can thus be obtained from different methods, the simplest being probably the linearized classical equations of motion.
What is spin waves and Magnons?
A spin wave is a propagating disturbance in the ordering of a magnetic material. From the equivalent quasiparticle point of view, spin waves are known as magnons, which are bosonic modes of the spin lattice that correspond roughly to the phonon excitations of the nuclear lattice.
How are spin waves formed?
If we now deflect one or a few of this magnetic moments from their equilibrium position the surrounding moments will “feel” this, as every magnetic moment produces a small magnetic field, so they will also be deflected a bit, then the next surrounding moments feels this and gets also deflected, in this way a wave of …
What are antiferromagnetic Magnons?
The elementary spin excitations in strongly magnetic materials are collective spin deviations, or spin waves, whose quanta are called magnons. Antiferromagnets are magnetic materials that have no net macroscopic magnetization and, therefore, are almost insensitive to external magnetic fields.
Why is Magnon a boson?
A magnon is a quasiparticle, a collective excitation of the electrons’ spin structure in a crystal lattice. Magnons carry a fixed amount of energy and lattice momentum, and are spin-1, indicating they obey boson behavior.
Can the spin wave contribute to specific heat of the material?
A direct differentiation of (1) with respect to T will therefore yield the magnetic specific heat Cm(T) of the material due to the excitation of the spin waves at. that particular temperature.
Why is magnon a boson?
What is the magnon in physics?
Magnon, small quantity of energy corresponding to a specific decrease in magnetic strength that travels as a unit through a magnetic substance. Related Topics: Quasiparticle Spin wave. In a magnetic substance, such as iron, each atom acts as a small individual magnet.
What is ferromagnetism and antiferromagnetism?
Ferromagnetism is the presence of magnetic domains that are aligned in the same direction in magnetic materials. Antiferromagnetism is the presence of magnetic domains that are aligned in opposite directions in magnetic materials.
Are Magnons bosons?
7.6. A spin wave is a propagating disturbance in local magnetic ordering; the magnon is the spin-wave quantum, a boson, associated with the flip of a single spin.
Is photon a quasiparticle?
In materials, a photon quasiparticle is a photon as affected by its interactions with the material. A polaron is a quasiparticle which comes about when an electron interacts with the polarization of its surrounding ions. An exciton is an electron and hole bound together.
Is magnon a boson?
How to investigate spin wave dynamics in antiferromagnetic?
Here we investigate spin-wave dynamics in antiferromagnetic CrI 3 bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique. Monolayer WSe 2 with a strong excitonic resonance was introduced on CrI 3 to enhance the optical excitation of spin waves.
Which is a bilayer antiferromagnet with spin waves?
Here we investigate spin-wave excitations in bilayer CrI 3, a model A-type antiferromagnet, using the time-resolved magneto-optical Kerr effect (MOKE). Magnetic resonances in bulk layered magnets were studied recently, which included CrI 3 and CrCl 3 by neutron scattering and microwave absorption 20, 21, 22.
What are the quanta of spin waves called?
The quanta of spin waves are called magnons. The rich spin-wave phenomena in magnetic materials have attracted fundamental interest and impacted on the technology of telecommunication systems, radars and, potentially, also low-power information transmission and processing 13. The main magnetic materials of interest have so far been ferromagnets.
Which is a type of antiferromagnetic coupled FM?
The recent discovery of 2D layered magnetic materials 15, 16, 17, particularly A-type antiferromagnets, which are antiferromagnetically coupled FM layers 15, presents new opportunities to unlock the properties of antiferromagnets. With fully uncompensated FM surfaces, the magnetic state can be easily accessed and controlled 18.