Emergent magnetic monopoles controlled at room temperature

Date:
August 6, 2021
Source:
University of Vienna
Summary:
Three dimensional (3D) nano-network promise a new era in modern
solid state physics with numerous applications in photonics,
bio-medicine, and spintronics. The realization of 3D magnetic
nano-architectures could enable ultra-fast and low-energy data
storage devices. Due to competing magnetic interactions in these
systems magnetic charges or magnetic monopoles can emerge, which
can be utilized as mobile, binary information carriers. Researchers
have now designed the first 3D artificial spin ice lattice hosting
unbound magnetic charges. The magnetic monopoles are stable at
room temperature and can be steered on-demand by external magnetic
fields.



FULL STORY ========================================================================== Emergent magnetic monopoles are observed in a class of magnetic
materials called spin ices. However, the atomic scales and required low temperatures for their stability limit their controllability. This led
to the development of 2D artificial spin ice, where the single atomic
moments are replaced by magnetic nano-islands arranged on different
lattices. The up-scaling allowed the study of emergent magnetic monopoles
on more accessible platforms. Reversing the magnetic orientation of
specific nano-islands propagates the monopoles one vertex further,
leaving a trace behind. This trace, Dirac Strings, necessarily stores
energy and bind the monopoles, limiting their mobility.


========================================================================== Researchers around Sabri Koraltan and Florian Slanovc, and led by
Dieter Suess at the University of Vienna, have now designed a first 3D artificial spin ice lattice that combines the advantages of both atomic-
and 2D artificial spin ices.

In a cooperation with Nanomagnetism and Magnonics group from University
of Vienna, and Theoretical Division of Los Alamos Laboratory, USA,
the benefits of the new lattice are studied employing micromagnetic simulations. Here, flat 2D nano-islands are replaced by magnetic
rotational ellipsoids, and a high symmetry three-dimensional lattice
is used. "Due to the degeneracy of the ground state the tension of the
Dirac strings vanish unbinding the magnetic monopoles," remarks Sabri
Koraltan, one of the first-authors of the study. The researchers took the
study further to the next step, where in their simulations one magnetic monopole was propagated through the lattice by applying external magnetic fields, demonstrating its application as information carriers in a 3D
magnetic nano-network.

Sabri Koraltan adds "We make use of the third dimension and high
symmetry in the new lattice to unbind the magnetic monopoles, and move
them in desired directions, almost like true electrons." The other
first-author Florian Slanovc concludes, "The thermal stability of the
monopoles around room temperature and above could lay the foundation
for ground breaking new generation of 3D storage techonologies." ========================================================================== Story Source: Materials provided by University_of_Vienna. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Sabri Koraltan, Florian Slanovc, Florian Bruckner, Cristiano Nisoli,
Andrii V. Chumak, Oleksandr V. Dobrovolskiy, Claas Abert, Dieter
Suess.

Tension-free Dirac strings and steered magnetic charges in 3D
artificial spin ice. npj Computational Materials, 2021; 7 (1) DOI:
10.1038/s41524- 021-00593-7 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210806104331.htm

--- up 13 weeks, 22 hours, 45 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)