Magnons

Magnetic inelastic scattering of neutrons

By Martin Böhm, Alain Filhol, Mathieu Ippersiel and Yannick Raoul. ©2013-2018 Institut Laue-Langevin.

Magnons is a 3D animation demonstrating the interaction of a neutron with the atomic spins of a magnetic crystal. To keep the animation simple, only one atomic layer is shown.

Magnons in short

The animation interface lets you adjust the temperature of the sample to modify the thermal motion of the atoms and spins; you can also apply a magnetic field to force the spins to align to varying degrees. This lets you explore all four phases (paramagnetic, ferromagnetic, antiferromagnetic, canted) shown in the top left insert. Each phase is characterized by a specific type of spin behaviour.
You can also throw a neutron at the sample and watch what happens. This will create a more or less pronounced collective motion of spins superimposed to the random thermal motion. This type of collective excitation of the lattice of spins is called a magnon, while a similar excitation of the atom lattice is known as a phonon. Phonons and magnons can be conveniently observed with the help of a neutron three-axis spectrometer.

Credits

Magnons is part of the application Neutrons4Science which is available for macOS, Windows, Linux, iOS and (soon ?) Android. It was initially developed in OpenGL by the firm IPTER (now out of business) . It has been redeveloped in webGL by Yannick Raoul and the ILL.