Tokiwa Y, Mchalwat M, Perry R S, Gegenwart P
I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
Phys Rev Lett. 2016 Jun 3;116(22):226402. doi: 10.1103/PhysRevLett.116.226402. Epub 2016 May 31.
Bilayer strontium ruthenate Sr_{3}Ru_{2}O_{7} displays pronounced non-Fermi liquid behavior at magnetic fields around 8 T, applied perpendicular to the ruthenate planes, which previously has been associated with an itinerant metamagnetic quantum critical end point (QCEP). We focus on the magnetic Grüneisen parameter Γ_{H}, which is the most direct probe to characterize field-induced quantum criticality. We confirm quantum critical scaling due to a putative two-dimensional QCEP near 7.845(5) T, which is masked by two ordered phases A and B, identified previously by neutron scattering. In addition, we find evidence for a QCEP at 7.53(2) T and determine the quantum critical regimes of both instabilities and the effect of their superposition.
双层钌酸锶（Sr₃Ru₂O₇）在垂直于钌酸盐平面施加的约8 T磁场下表现出明显的非费米液体行为，此前这种行为与巡游变磁性量子临界端点（QCEP）有关。我们聚焦于磁格林艾森参数Γₕ，它是表征场诱导量子临界性的最直接探针。我们证实了由于在7.845(5) T附近假定的二维QCEP导致的量子临界标度，该QCEP被先前通过中子散射识别出的两个有序相A和B所掩盖。此外，我们发现了在7.53(2) T处存在QCEP的证据，并确定了两种不稳定性的量子临界区域及其叠加效应。
