NÉEL INSTITUTE Grenoble
Topic for Master 2 internship – Academic year 2020-2021
MAGNETIC FRUSTRATION IN A NEW PYROCLHORE FAMILY
General Scope:
The pyrochlore lattice featuring corner sharing tetrahedra has been a playground for magnetic frustration effects [1]. An example of exotic phases that may emerge is the so-called spin ice – as referred to water ice with its O-H bonds – where, on each tetrahedron, two spins point inward and the others outward. This is a highly degenerate state (there are many possible spin configurations) that can be viewed as a spin liquid with original short-range correlations. Another exotic phase is magnetic fragmentation [2]: in this new state of matter, the magnetic moment fragments into an ordered part and a persistently fluctuating one.
Research topic and facilities available:
There are only few compounds with a magnetic pyrochlore lattice. Recently a new family has been synthetized at Néel Institute: R2NbScO7 where R is a rare earth element. These compounds are all the most original that Nb5+ and Sc 3+ are also arranged on a pyrochlore lattice where possible “electric charge ice” may be realized. This opens very interesting possibilities of entanglement of electric and magnetic exotic behaviors, that we plan to unveil.
The student will study the magneto-electric properties of these compounds using characterization tools available at Néel Institute as well as sophisticated neutron diffraction techniques available at the neutron source ILL.
Possible collaboration and networking:
The student will use several experimental equipment available in different technical groups and platforms (bulk crystal /Magnetometry / Automatization & characterization). She/he will interact with researchers from the MagSup team as well as scientists from ILL.
Possible extension as a PhD: yes
Required skills: Prerequisite in Solid Physics and Magnetism.
Starting date: Spring 2020 Contact:
Name: Sophie DE BRION / Virginie SIMONET Institut Néel - CNRS
e-mail: [email protected] , [email protected]
More information: http://neel.cnrs.fr
[1] See for instance: Gardner et al, Review of Modern Physics 82, 53 (2010) arxiv.org/abs/0906.3661 [2] E .Lefrançois et al, Nature Commun. 8, 209 (2017) arxiv.org/abs/1704.00915
(a) (b)
The pyrochlore network with corner sharing tetrahedra (a). 2-in 2-out ice rule in one tetrahedron (b).
