P- 31 NMR investigation of quasi-two-dimensional magnetic correlations in( )T(2)P(2)S( 6) (T=Mn, Ni)

Article

关键词: OPTICAL-ABSORPTION SPECTRA;    SPIN DYNAMICS;    CRITICAL-BEHAVIOR;    P-31 NMR;    MPS3 M;    TRANSITION;    RELAXATION;    CRYSTAL;    PHASE;    THIOPHOSPHATE;   

DOI  :  10.1103/PhysRevB.105.024410

来源: SCIE

【 摘 要 】

We report the anomalous breakdown in the scaling of the microscopic magnetic susceptibility-as measured via the 31P nuclear magnetic resonance (NMR) shift K-with the bulk magnetic susceptibility chi in the paramagnetic state of Mn2P2S6. This anomaly occurs near Tmax similar to 117 K the maximum in chi(T ) and is therefore associated with the onset of quasi-two-dimensional (quasi-2D) magnetic correlations. The spin-lattice relaxation rate divided by temperature (T1T )-1 in Mn2P2S6 exhibits broad peaklike behavior as a function of temperature, qualitatively following chi, but displaying no evidence of critical slowing down above the Neel temperature TN. In the magnetic state of Mn2P2S6, NMR spectra provide good evidence for 60 degrees rotation of stacking-fault-induced magnetic domains, as well as observation of the spin-flop transition that onsets at 4 T. The temperature-dependent critical behavior of the internal hyperfine field at the P site in Mn2P2S6 is consistent with previous measurements and the two-dimensional anisotropic Heisenberg model. In a sample of Ni2P2S6, we observe only two magnetically split resonances in the magnetic state, demonstrating that the multiple-peaked NMR spectra previously associated with 60 degrees rotation of stacking faults is sample-dependent. Finally, we report the observation of a spin-flop-induced splitting of the NMR spectra in Ni2P2S6, with an onset spin-flop field of mu 0Hsf = 14 T.

【 授权许可】

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