In this paper we report the synthesis, magnetization and heat capacity of the frustrated magnets emph{A}ErSe$_2$(emph{A}=Na,K) which contain perfect triangular lattices of Er$^{3+}$. The magnetization data suggests no long-range magnetic order exists in emph{A}ErSe$_2$(emph{A}=Na,K), which is consistent with the heat capacity measurements. Large anisotropy is observed between the magnetization within the emph{ab} plane and along the emph{c} axis of both compounds. When the magnetic field is applied along emph{ab} plane, anomalies are observed at 1.8 $mu_B$ in NaErSe$_2$ at 0.2 T and 2.1 $mu_B$ in KErSe$_2$ at 0.18 T. Unlike NaErSe$_2$, a plateau-like field-induced metamagnetic transition is observed for H$|$emph{c} below 1 K in KErSe$_2$. Two broad peaks are observed in the heat capacity below 10 K indicating possible crystal electric field(CEF) effects and magnetic entropy released under different magnetic fields. All results indicate that emph{A}ErSe$_2$ are strongly anisotropic, frustrated magnets with field-induced transition at low temperature. The lack of signatures for long-range magnetic order implies that these materials are candidates for hosting a quantum spin liquid ground state.
تحميل البحث