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Detail práce
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The search for new spin-liquid materials – synthesis of kagome magnets through depletion of the pyrochlore lattice.
Název práce v češtině: The search for new spin-liquid materials – synthesis of kagome magnets through depletion of the pyrochlore lattice.
Název v anglickém jazyce: The search for new spin-liquid materials – synthesis of kagome magnets through depletion of the pyrochlore lattice.
Klíčová slova anglicky: Magnetism, Synthesis, Quantum spin liquid
Akademický rok vypsání: 2017/2018
Typ práce: projekt
Jazyk práce:
Ústav: Katedra fyziky kondenzovaných látek (32-KFKL)
Vedoucí / školitel: Ross Harvey Colman, Dr.
Řešitel:
Zásady pro vypracování
1. Prepare sample
2. Characterise sample by magnetometry and X-ray diffraction
3. Write a report
Seznam odborné literatury
[1] Balents, L. Nature (2010) 464, 199.
[2] Clark, B. Physics (2017) 10, 33 [physics.aps.org/articles/v10/33].
[3] Sanders, M. B. et al. J. Mater. Chem. C (2016) 4, 541.
[4] Sanders, M. B. et al. Phys. Status Solidi B (2016) 253, 2056.
[5] Scheie, A. et al. Rhys. Rev. B (2016) 93, 180407(R).
[6] Fu, W.T. et al. J. Solid State Chem. (2014) 213, 165.
[7] Li, K. et al. J. Solid State Chem. (2014) 217, 80.
[8] Mumme, W. G. Am. Miner. (2010) 95, 736.
Předběžná náplň práce
The study of emergent phenomena considers how a simple set of interactions between microscopic components in a system can lead to unexpected macroscopic properties, such as consciousness arising from interactions between neurones or complex weather systems arising from interactions between air molecules. Geometrically frustrated magnets are an ideal place to study emergent phenomena due to the relevant simplicity of magnetic interactions [1]. Geometric frustration, where the lattice geometry prevents the simultaneous satisfaction of all the magnetic interactions, is one way of creating unconventional magnetic ground-states and a can provide convenient models for studying emergent phenomena. Antiferromagnetically coupled magnetic ions on a kagome lattice, a lattice built of vertex sharing triangles, is considered one of the most highly frustrated types of arrangements and there have been long debates about the nature of the ground-state that should emerge on such a lattice, lasting for over a decade [2].
One key point that has perpetuated this discussion is the lack of good model materials to investigate such a situation experimentally. Some models exist but every model material has associated problems that prevent us reaching a definitive answer to the question.
One method of creating a kagome lattice is through the ordered dilution of a pyrochlore lattice, made up of vertex sharing tetrahedra. This has been seen in several rare-earth materials recently with the general formula RE3M2Sb3O14 (RE = rare earth ion, M = Zn, Mg, Mn or Co) [3-7] and is seen in the mineral with formula CaNa3AlMg3F14 [8]. Due to the chemical similarity between Mg2+ (diamagnetic) and Cu2+ (magnetically active, s=1/2 ion), and their similar ionic radii 0.72 vs. 0.73 Å3, respectively, this project will aim to synthesise a new kagome material with formula CaNa3AlCu3F14, through solid state synthesis techniques from fluoride salt precursors. Once synthesised, the magnetic and electrical properties will be investigated and other chemical substitutions can be attempted.

Předběžná náplň práce v anglickém jazyce
The study of emergent phenomena considers how a simple set of interactions between microscopic components in a system can lead to unexpected macroscopic properties, such as consciousness arising from interactions between neurones or complex weather systems arising from interactions between air molecules. Geometrically frustrated magnets are an ideal place to study emergent phenomena due to the relevant simplicity of magnetic interactions [1]. Geometric frustration, where the lattice geometry prevents the simultaneous satisfaction of all the magnetic interactions, is one way of creating unconventional magnetic ground-states and a can provide convenient models for studying emergent phenomena. Antiferromagnetically coupled magnetic ions on a kagome lattice, a lattice built of vertex sharing triangles, is considered one of the most highly frustrated types of arrangements and there have been long debates about the nature of the ground-state that should emerge on such a lattice, lasting for over a decade [2].
One key point that has perpetuated this discussion is the lack of good model materials to investigate such a situation experimentally. Some models exist but every model material has associated problems that prevent us reaching a definitive answer to the question.
One method of creating a kagome lattice is through the ordered dilution of a pyrochlore lattice, made up of vertex sharing tetrahedra. This has been seen in several rare-earth materials recently with the general formula RE3M2Sb3O14 (RE = rare earth ion, M = Zn, Mg, Mn or Co) [3-7] and is seen in the mineral with formula CaNa3AlMg3F14 [8]. Due to the chemical similarity between Mg2+ (diamagnetic) and Cu2+ (magnetically active, s=1/2 ion), and their similar ionic radii 0.72 vs. 0.73 Å3, respectively, this project will aim to synthesise a new kagome material with formula CaNa3AlCu3F14, through solid state synthesis techniques from fluoride salt precursors. Once synthesised, the magnetic and electrical properties will be investigated and other chemical substitutions can be attempted.

 
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