Magnetic-field- and pressure-induced quantum phase transition in CsFeCl3 proved via magnetization measurements

摘要

We have performed magnetization measurements of the gapped quantum magnet CsFeCl3 at temperatures (T) down to 0.5 K at ambient pressure and down to 1.8 K at hydrostatic pressures (P) of up to 1.5 GPa. The lower-field (H) phase boundary of the field-induced ordered phase at ambient pressure is found to follow the power-law behavior expressed by the formula H-N(T) - H-c alpha T-N(phi) . The application of pressure extends the phase boundary to both a lower field and higher temperature. Above the critical pressure P-c similar to 0.9 GPa, the transition field HN associated with the excitation gap becomes zero, and a signature of the magnetic phase transition is found in the T dependence of magnetization in a very low applied field. This suggests that CsFeCl3 exhibits a pressure-induced magnetic phase transition at Pc.