Magnetic field-driven quantum criticality in antiferromagnetic CePtIn ₄

Abstract

Physics of quantum critical point is one of the most perplexing topics in current condensed-matter physics. Its conclusive understanding is forestalled by the scarcity of experimental systems displaying novel aspects of quantum criticality. We present a comprehensive experimental evidence of a magnetic field tuned tricritical point separating paramagnetic, antiferromagnetic and metamagnetic phases in novel CePtIn4. Analyzing field variations of its magnetic susceptibility, magnetoresistance and specific heat at very low temperatures we trace modifications of antiferromagnetic structure of the compound. Upon applying magnetic field of increasing strength, the system undergoes metamagnetic transitions which persist down to the lowest temperature investigated, exhibiting first-order-like boundaries separating magnetic phases. This yields a unique phase diagram where the second-order phase transition line terminates at a tricritical point followed by two first-order lines reaching quantum critical end points as T  0. Our findings demonstrate that CePtIn4 provides innovative perspective for studies of quantum criticality.

Successive magnetic transitions in the heavy-fermion superconductor Ce3PtIn11 studied by In115 nuclear quadrupole resonance

“…Ce-based intermetallic systems have gained considerable research interest due to their diverse and perplexing physical properties encompassing observation of non-Fermi-liquid behavior, heavy-fermion superconductivity, and quantum criticality [1][2][3][4][5]. Among the vast number of known compounds, the members of the Ce n M m In 3n+2m (M = Co, Rh, Pd, Ir, Pt) family have drawn an unprecedented amount of research effort due to their fascinating phase diagrams, which allow exploration of the relationship between magnetism and adjacent superconductivity.…”

Unveiling the Physics of the Mutual Interactions in Paramagnets

“…It is well-established that for a pressure-induced QCP 22,23 , as well as for a finite temperature (T) pressure-induced critical point [24][25][26] , the Grüneisen ratio, i.e., the ratio between thermal expansivity and specific heat at constant pressure, is enhanced upon approaching the critical values of the tuning parameter and it diverges right at the critical point. For a magnetic field-induced QCP 27 the analogous physical quantity to the Grüneisen ratio is the so-called magnetic Grüneisen parameter, hereafter Γ mag 22,28,29 . The enhancement of both the Grüneisen ratio and Γ mag in the immediate vicinity of a magnetic field-induced QCP is merely a direct consequence of the high entropy accumulation in that region 22,23 , which in turn is related to the fluctuations of the order parameter.…”

Entropic topography associated with field-induced quantum criticality in a magnetic insulator DyVO4

“…It implies that the MMT becomes stronger at lower temperature. This observation suggests that quantum fluctuations may play an important role in governing the field-driven transitions, as T → 0 and the tuning parameter H is likely to perturbate these quantum fluctuations 20 . Also, the position of maximum corresponding to the MMT as a function of H i appears to be sensitive to temperature and therefore, temperature response of critical field associated with MMT demands attention.…”

“…To clearly visualize the change of slope, field response of d M /d H i at selected temperatures in the AFM state is shown in Fig. 2 c. Here, the maxima corresponding to each curve is ascribed to the MMT 20 , 35 . Also, it is noted that the peaks in d M /d H i sharpens and an increase in height is observed as the temperature is decreased.…”

“…T dependence of this quantity also shows a hyperbolic divergence with decreasing T for H m , which is attributed to the quantum phase transition 12 . Field induced quantum criticality has been reported in many systems, such as in CoNb 2 O 6 8 , CeAuSb 2 13 , CeCoIn 5 14 , YbRh 2 Si 2 15 , 16 , Sr 3 Ru 2 O 7 17 – 19 , CePtIn 4 20 and many more. Field tuned anomalous quantum criticality has also been observed in Y-substituted CeNiGe 2 21 .…”