High pressure electrical resistivity and specific heat of the heavy fermion compound CeCoGe2.2Si0.8

Part of Special Issue on Quantum Criticality and Novel Phases



We study the evolution of the magnetic ground state close to the putative quantum critical point in CeCoGe2.2Si0.8 by using electrical resistivity and specific heat measurements under the same high hydrostatic pressure conditions. The electrical resistivity shows that the antiferromagnetic ordering temperature, TN, is suppressed above PC = 5.9 kbar, with the emergence of non-Fermi liquid behavior. On the other hand, the specific heat shows two different magnetic transitions at 0 kbar, one at TN and another one at Tl 0.3 K. Both transition temperatures are reduced by pressure but remain finite up to at least 7.2 kbar. The height of the specific heat anomaly at TN, ΔCN, is strongly reduced above PC. These features suggest that the quantum criticality in CeCoGe2.2Si0.8 is governed by disorder.