28 August 2022 to 2 September 2022
Science and Technology Campus, University of Parma
Europe/Rome timezone
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Universal fluctuating regime in triangular chromate pure Heisenberg S=3/2 antiferromagnets

1 Sep 2022, 09:40
20m
Science and Technology Campus, University of Parma

Science and Technology Campus, University of Parma

University of Parma, Italy
Oral Spin liquids and related phenomena Oral contributions

Speaker

Philippe Mendels (Université Paris(Sacaly)

Description

The series of triangular compounds ACrO$_2$ is a model series for studying the Heisenberg model on S=3/2 (Cr$^{3+}$: half-filled t$_{2g}$ orbitals) triangular antiferromagnets and the impact of interlayer couplings on the dynamics. For this, we report µSR measurements on α-HCrO$_2$ and KCrO$_2$ [1] which complete former studies on the series of triangular compounds ACrO$_2$, A = Li , Na [2, 3]. Coupled to $^1$H and $^{39}$K nuclear magnetic resonance (NMR), we establish the static character at low-T, as expected for a near neighbour Heisenberg model, yet displaying a broad and remarkable regime with slow fluctuations extending from $T_N$ down to 0.2 $T_N$. This regime is marked by a maximum in the μSR relaxation rate occuring at 0.7 $T_N$, associated with an NMR wipe-out .
The scaling of the NMR and μSR data with respect to J or T$_N$ supports a scenario where a crossover from 2D to 3D correlations sets in around 0.7 T$_N$ preceded by a typical 2D regime of the TLHAF which appears to be a hallmark of the TLHAF with ABC stacking. We discuss the role of interlayer frustration which may bear implications to recent spin-liquid candidates with the triangular geometry and exclude a scenario à la Berezinskii-Kostelitz-Touless of vortex-antivortex topological excitations in that regime. In turn, this underlines the crucial need of further neighbour interactions, anisotropy typical of rare earth or even disorder to stabilize a quantum spin liquid state in triangular antiferromagnets such as YbMgGaO$_4$.
[1] K. Somesh et al. Phys. Rev. B 104, 104422 (2021).
[2] A. Olariu et al. Phys. Rev. Lett. 97, 167203 (2006).
[3] A. Olariu et al. Phys. Rev. B 79, 224401 (2009).

Primary author

Philippe Mendels (Université Paris(Sacaly)

Co-authors

Dr G. Simutis (Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland) Prof. Fabrice Bert (Université Paris-Sacaly) Prof. Ramesh Nath (IISER Thiruvananthapuram) Dr K Somesh (IISER Thiruvananthapuram) Dr Andrej Zorko (Jozef Stefan Institute) Dr Alexander Tsirlin (Augsburg Univ) Prof. Yuji Furukawa (Iowa State Univ.)

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