- Krisitna Vlášková: Magnetic properties of rare-earth iridates
- 16. 11. 2022, 14:10
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The geometrical frustration in A2B2O7 pyrochlores significantly affects both A and B lattices and may lead to complex low-temperature states with possible future applications. The family of rare-earth pyrochlore iridates introduces also an interplay between spin-orbit coupling and electron correlations, inherent to iridium ions, which may lead to topologically non-trivial electron states. The route for A2Ir2O7synthesis from polycrystal to single crystal samples will be commented. The results of standard bulk magnetization measurement will be confronted with the experiments of neutron scattering and muon spin resonance. An evolution of iridium magnetic ordering was followed for heavy rare-earth part of the series, following the trend throughout this family. An emergence of oscillations in muon spin rotation spectra unambiguously proved the existence of long-range iridium ordering. Another aspect of the iridium magnetism was probed by the AC susceptibility measurement and the results were discussed in the frame of the model considering weakly bounded spins at the antiferromagnetic domain walls in the material, which appears to be universal within the A2Ir2O7family. Based on the measurement of single ion properties of individual rare-earth, the influence on static and dynamic part of iridium magnetism was followed. Besides, a standard crystal field model for respective A3+inferred from the inelastic neutron scattering was confronted with magnetic properties. The mutual agreement suggests, that the rare-earth ions governs the behaviour at higher temperatures and magnetic fields.