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arXiv · 2207.01284

One-Dimensional Quantum Magnetism in the S = 1/2 Mo(V) system, KMoOP2O7

Aly H. Abdeldaim·Alexander A. Tsirlin·Jacques Ollivier·Clemens Ritter·Dominic Fortes·Robin S. Perry·Lucy Clark·Gøran J. Nilsen
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Abstract

We present a comprehensive experimental and ab-initio study of the $S=1/2$ Mo$^{5+}$ system, KMoOP$_2$O$_7$, and show that it realizes the $S = 1/2$ Heisenberg chain antiferromagnet model. Powder neutron diffraction reveals that KMoOP$_2$O$_7$ forms a magnetic network comprised of pairs of Mo$^{5+}$ chains within its monoclinic $P2_1/n$ structure. Antiferromagnetic interactions within the Mo$^{5+}$ chains are identified through magnetometry measurements and confirmed by analysis of the magnetic specific heat. The latter reveals a broad feature centred on $T_\textrm{N} = 0.54$ K, which we ascribe to the onset of long-range antiferromagnetic order. No magnetic Bragg scattering is observed in powder neutron diffraction data collected at 0.05 K, however, which is consistent with a strongly suppressed ordered moment with an upper limit $\mu_\textrm{ord} < 0.15 \mu_\textrm{B}$. The one-dimensional character of the magnetic correlations in KMoOP$_2$O$_7$ is verified through analysis of inelastic neutron scattering data, resulting in a model with $J_\textrm{1} \approx 34$ K and $J_\textrm{2} \approx -2$ K for the intrachain and interchain exchange interactions, respectively. The origin of these experimental findings are addressed through density-functional theory calculations.

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Aly H. Abdeldaim, Alexander A. Tsirlin, Jacques Ollivier, Clemens Ritter, Dominic Fortes, Robin S. Perry, Lucy Clark, Gøran J. Nilsen. 2022-07-04. One-Dimensional Quantum Magnetism in the S = 1/2 Mo(V) system, KMoOP2O7. https://doi.org/10.1103/physrevb.107.014415

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