Quasi-2D magnetic correlations in Ni${}_2$P${}_2$S${}_6$ probed by ${}^{31}$P NMR

Abstract

Detailed ${}^{31}$P nuclear magnetic resonance (NMR) measurements are presented on well-characterized single crystals of antiferromagnetic van der Waals Ni${}_2$P${}_2$S${}_6$. An anomalous breakdown is observed in the proportionality of the NMR shift $K$ with the bulk susceptibility $\chi$. This so-called $K$$-$$\chi$ anomaly occurs in close proximity to the broad peak in $\chi (T)$, thereby implying a connection to quasi-2D magnetic correlations known to be responsible for this maximum. Quantum chemistry calculations show that crystal field energy level depopulation effects cannot be responsible for the $K$$-$$\chi$ anomaly. Appreciable in-plane transferred hyperfine coupling is observed, which is consistent with the proposed Ni$-$S$-$Ni super- and Ni$-$S$-$S$-$Ni super-super-exchange coupling mechanisms. Magnetization and spin$-$lattice relaxation rate ($T_1^{-1}$) measurements indicate little to no magnetic field dependence of the Néel temperature. Finally, $T_1^{-1}(T)$ evidences relaxation driven by three-magnon scattering in the antiferromagnetic state.

16 pages, 16 figures, submitted to Phys. Rev. B

References in corpus (6)

• Ising-Type Magnetic Ordering in Atomically Thin FePS3
• Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3
• Long range order and two-fluid behavior in heavy electron materials
• Nuclear magnetic resonance in the heavy fermion superconductors
• Spin-state transition and spin-polaron physics in cobalt oxide perovskites: ab initio approach based on quantum chemical methods
• Direct observation of impurity-induced magnetism in an S = 1/2 antiferromagnetic Heisenberg 2-leg spin ladder