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Effect of disorder on a pressure-induced z=1 magnetic quantum phase transition

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Mannig A., Moller J. S., Thede M., Huvonen D., Lancaster T., Xiao F., Williams R. C., Guguchia Z., Khasanov R., Morenzoni E., Zheludev A.,
Project Interplay between the superconductivity and magnetism in cuprate and Fe-based superconductors
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Original article (peer-reviewed)

Volume (Issue) 94(14)
Page(s) 144418
Title of proceedings PHYSICAL REVIEW B
DOI 10.1103/physrevb.94.144418


Pressure-induced ordering close to a z = 1 quantum-critical point is studied in the presence of bond disorder in the quantum spin system (C4H12N2)Cu-2(Cl1-xBrx)(6) (PHCX) by means of muon-spin rotation and relaxation. As for the pure system (C4H12N2)Cu2Cl6, pressure allows PHCX with small levels of disorder (x <= 7.5\%) to be driven through a quantum-critical point separating a low-pressure quantum paramagnetic phase from magnetic order at high pressures. However, the pressure-induced ordered state is highly inhomogeneous for disorder concentrations x > 1\%. This behavior might be related to the formation of a quantum Griffiths phase above a critical disorder concentration 7.5\% < x(c) < 15\%. Br substitution increases the critical pressure and suppresses critical temperatures and ordered moment sizes.