Frustrated lattices of electric and magnetic dipoles

• Thesis title in Czech: Frustrované mřížky magnetických a elektrických dipólů
• Thesis title in English: Frustrated lattices of electric and magnetic dipoles
• Key words: magnetism|magnetic frustration|magnetoelectricity|multiferroicity|crystal growth
• English key words: magnetism|magnetic frustration|magnetoelectricity|multiferroicity|crystal growth
• Academic year of topic announcement: 2021/2022
• Thesis type: dissertation
• Thesis language: angličtina
• Department: Department of Condensed Matter Physics (32-KFKL)
• Supervisor: Ross Harvey Colman, Dr.
• Author: hidden - assigned and confirmed by the Study Dept.
• Date of registration: 08.02.2022
• Date of assignment: 08.02.2022
• Confirmed by Study dept. on: 14.02.2022

Guidelines

-Litterature study on frustrated magnetism
-Single crystal growth of selected compounds, mainly using the floating zone method
-Structural analysis of the crystals
-Measurements of physical properties such as magnetization, specific heat or electric permittivity down to low temperatures and under various applied magnetic fields in different directions.
-Application for measurements on large scale facilities, such as neutron scattering or muon spectroscopy and conduction of such measurements if they are accepted.
-Redaction of publications and of the dissertation

References

[1] Y. Li, P. Gegenwart, and A. A. Tsirlin. Spin liquids in geometrically perfect triangular antiferromagnets. Journal of Physics: Condensed Matter, IOP Publishing 2020, 32, 224004. https://iopscience.iop.org/article/10.1088/1361-648X/ab724e
[2] Savary, L.; Balents, L. Quantum Spin Liquids: A Review. Reports Prog. Phys. 2017, 80 (1), 016502. https://doi.org/10.1088/0034-4885/80/1/016502
[3] S.-P. Shen, J.-C. Wu, J.-D. Song, X.-F. Sun, Y.-F. Yang, Y.-S. Chai, D.-S. Shang, S.-G. Wang, J. F. Scott, and Y. Sun, , Quantum electric-dipole liquid on a triangular lattice, Nature Communications 2016, 7. https://doi.org/10.1038/ncomms10569
[4] M. Ashtar, Y. X. Gao, C. L. Wang, Y. Qiu, W. Tong, Y. M. Zou, X. W. Zhang, M. A. Marwat, S. L. Yuan, and Z. M. Tian, Synthesis, structure and magnetic properties of rare-earth remgal11o19 (re = pr, nd) with two-dimensional triangular lattice, Journal of Alloys and Compounds 2019, 802, 146. http://www.sciencedirect.com/science/article/pii/S0925838819322613
[5] K. Geirhos, P. Lunkenheimer, M. Blankenhorn, R. Claus, Y. Matsumoto, K. Kitagawa, T. Takayama, H. Takagi, I. Kezsmarki, and A. Loidl, Quantum paraelectricity in the kitaev quantum spin-liquid candidates H3LiIr2O6 and D3LiIr2O6, Phys. Rev. B 2020, 101, 184410. https://doi.org/10.1103/physrevb.101.184410
[6] Alemayehu S. Admasu, Durga Sankar Vavilapalli, The Laser-Diode Heated Floating Zone Method for Automated Optimal Synthesis of Refractory Oxides and Alloys, https://arxiv.org/abs/2103.05587
[7] S. Dong, J.-M. Liu, S.-W. Cheong, and Z. Ren, Multiferroicmaterials and magnetoelectric physics: symmetry, entanglement, excitation, and topology, Advances in Physics 2015, 64, 519. https://doi.org/10.1080/00018732.2015.1114338

Preliminary scope of work in English

The thesis consists in the study of potentially frustrated lattices of electric and magnetic dipolar moments. This objective will be achieved via the crystal growth and physical properties characterization of the compounds LnMgAl11O19 (Ln=Ce , Pr, Nd). These compounds harbor both triangular lattices of magnetic dipolar moments stting on the lanthanide site (Ce , Pr or Nd) and triangular lattices of electric dipolar moments formed by bipyramid AlO5. Frustration is expected in these materials in the sense that all the magnetic or electric interactions cannot be simultaneously satisfied. This frustration is expected to lead to the competition between various possible ground states including magnetically ordered states but also disordered states such as the so called quantum spin liquid state.
The work will aim at the characterization of the magnetic ground state and field induced phases in LnMgAl11O19 (Ln=Ce , Pr, Nd) and a particular interest will be given to the coupling between the structural, magnetic and dielectric properties. The work will consist of crystal growth, structural analysis and measurements of physical properties such as magnetization and specific heat measurements down to subkelvin temperature. In addition, few measurements on large scale facilities, such as neutron scattering or muon spectroscopy may be part of the work.