Incommensurate Magnetic Order in Sm₃BWO₉ with Distorted Kagome Lattice

【摘要】 We investigate the magnetic ground state of Sm₃BWO₉ with a distorted kagome lattice.A magnetic phase transition is identified at T_N=0.75 K from the temperature dependence of specific heat.From ¹¹B nuclear magnetic resonance measurements,an incommensurate magnetic order is shown by the double-horn type spectra under a c-axis magnetic field,and absence of line splitting is observed for field oriented within theαb-plane,indicating the incommensurate modulation of the internal field strictly along c-axis.From the spin dynamics,the critical slowing-down behavior is observed in the temperature dependence of 1/T₁ withμ₀H⊥c-axis,which is completely absent in the case with μ₀H||c-axis.Based on the local symmetry of ¹¹B sites,we analyze the hyperfine coupling tensors and propose two constraints on the possible magnetic structure.The single ion anisotropy should play an important role in determination of contrasting ground states of Sm₃BWO₉ and Pr₃BWO₉.更多还原

【Abstract】 We investigate the magnetic ground state of Sm₃BWO₉ with a distorted kagome lattice.A magnetic phase transition is identified at T_N=0.75 K from the temperature dependence of specific heat.From ¹¹B nuclear magnetic resonance measurements,an incommensurate magnetic order is shown by the double-horn type spectra under a c-axis magnetic field,and absence of line splitting is observed for field oriented within theαb-plane,indicating the incommensurate modulation of the internal field strictly along c-axis.From the spin dynamics,the critical slowing-down behavior is observed in the temperature dependence of 1/T₁ withμ₀H⊥c-axis,which is completely absent in the case with μ₀H||c-axis.Based on the local symmetry of ¹¹B sites,we analyze the hyperfine coupling tensors and propose two constraints on the possible magnetic structure.The single ion anisotropy should play an important role in determination of contrasting ground states of Sm₃BWO₉ and Pr₃BWO₉.更多还原