The heavy fermion superconductor CeCoIn5 shows clear signatures of quantum critical fluctuations near the superconducting upper critical field Hc2, but their origin is still unresolved because relevant magnetic order has not yet been identified in this compound. Here, we demonstrate an emergence of new field-induced antiferromagnetic order coupled with quantum critical fluctuations in Zn-doped CeCoIn5. Scaling analysis for the specific heat data suggests that the quantum critical fluctuations seen in pure and Zn-doped CeCoIn5 have almost the same origin; the quantum critical fluctuations enhanced near Hc2 in pure CeCoIn5 originate from the "hidden" order parameter of the field-induced antiferromagnetic phase observed in Zn-doped CeCoIn5.
The article regarding this work:
M. Yokoyama, H. Mashiko, R. Otaka, Y. Oshima, K. Suzuki, K. Tenya, Y. Shimizu, A. Nakamura, D. Aoki, A. Kondo, K. Kindo, S. Nakamura, T. Sakakibara:
"Observation of a new field-induced phase transition and its concomitant quantum critical fluctuations in CeCo(In1-xZnx)5",
Physical Review B 95, 224425-1-5 (2017).
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