Magnetic Properties Of The Pressure-Induced Ordering State In Ybincu4 Investigated With Nmr, Magnetization, And X-Ray Diffraction Measurements

We have investigated the newly discovered pressure-induced magnetic ordering phase in YbInCu4 using dc magnetization, nuclear magnetic resonance (NMR), and x-ray diffraction measurements. The dc magnetization measurements provide evidence for the appearance of spontaneous magnetization above 3 GPa and enable us to establish a pressure-temperature phase diagram for YbInCu4 over a wide pressure range up to 27 GPa. It is shown that, while the valence transition temperature T-V is strongly reduced with increasing pressure, the magnetic ordering temperature T-M reveals a very weak pressure dependence. We find no evidence for any structural phase transition up to 15 GPa within the experimental accuracy. The Curie-Weiss temperature dependence of susceptibility in pressure-stabilized paramagnetic state is evaluated from the Knight shift data obtained from In-115 NMR measurements. From these experimental results, we discuss possible electronic states of the 4f electrons in the high pressure magnetically ordered phase of YbInCu4.