Appearance of a field-induced phase and a quantum critical line in pressurized Yb2Pd2Sn

We report three-dimensional pressure-field-temperature phase diagrams of Yb2Pd2Sn and Yb2(Pd0.9Ni0.1)2Sn that are constructed from electrical resistivity measurements. In Yb2Pd2Sn, which is known to be a pressure-induced antiferromagnet, we found an unexpected magnetic-field-induced phase at a higher field than the antiferromagnetic (AFM) phase under pressure. A non-Fermi-liquid (NFL) behavior characterized by T3/2 dependence of the resistivity is observed along the AFM phase boundary, indicating the existence of the quantum critical line. As the AFM and field-induced phases approach each other with increasing pressure, the NFL behavior is more pronounced. Yb2(Pd0.9Ni0.1)2Sn is known to be an antiferromagnet at ambient pressure. We also found a field-induced phase under pressure. Although the temperature-pressure phase diagram of Yb2(Pd0.9Ni0.1)2Sn corresponds to that of Yb2Pd2Sn shifted by 1.7 GPa, the field-induced phase does not separate from the AFM phase. Furthermore, the NFL behavior is less pronounced than Yb2Pd2Sn. The Ni substitution for Pd not only acts as a chemical pressure but also produces other effects for the magnetism and its criticality.