The resistivity of the heavy-fermion superconductor CeCoIn5 was measured as a function of temperature, down to 25 mK and in magnetic fields of up to 16 T applied perpendicular to the basal plane. With increasing field, we observe a suppression of the non-Fermi liquid behavior, rho ~ T, and the development of a Fermi liquid state, with its characteristic rho = rho_0 + AT^2 dependence. The field dependence of the T^2 coefficient shows critical behavior with an exponent of 1.37. This is evidence for a field-induced quantum critical point (QCP), occuring at a critical field which coincides, within experimental accuracy, with the superconducting critical field H_c2. We discuss the relation of this field-tuned QCP to a change in the magnetic state, seen as a change in magnetoresistance from positive to negative, at a crossover line that has a common border with the superconducting region below ~ 1 K.
@article{arxiv.cond-mat/0212502,
title = {Field-Induced Quantum Critical Point in CeCoIn5},
author = {Johnpierre Paglione and M. A. Tanatar and D. G. Hawthorn and Etienne Boaknin and R. W. Hill and F. Ronning and M. Sutherland and Louis Taillefer and C. Petrovic and P. C. Canfield},
journal= {arXiv preprint arXiv:cond-mat/0212502},
year = {2009}
}