Signature of Possible Spin Liquid State at 2 K in Spin-Frustrated Cr1-xFexPSe3 Alloy

Disordered spin systems typically exhibit glass-like characteristics below the glass transition temperature [1–4]. However, when the competition between ferromagnetic and antiferromagnetic couplings is balanced, the spin liquid state persists towards zero Kelvin [5]. This unique state is known as the quantum spin liquid state. In this study, we examined a potential spin liquid state in the two-dimensional spin-frustrated Cr1-xFexPSe3 alloy by magnetic susceptibility measurements as a function of temperature and doping. Two end compounds, CrPSe3 and FePSe3, exhibit a long-range magnetic order. With the Fe doping, the antiferromagnetic order of frustrated CrPSe3 gradually weakened and reached its minimum transition temperature at the critical concentration of x = 0.33. This weak order became indeterminate when a high magnetic field was applied, indicating the possibility of converting the magnetic order to the spin liquid state down to 2K. With further doping, an antiferromagnetic order was observed in the Fe-dominated compound. Our results provide a new two-dimensional flat form for exploring quantum spin liquid states.