Quantum phase transitions and decoupling of magnetic sublattices in the quasi-two-dimensional Ising magnet Co3 V2 O8 in a transverse magnetic field

The application of a magnetic field transverse to the easy axis, Ising direction in the quasi-two-dimensional kagome staircase magnet, Co3V2O8, induces three quantum phase transitions at low temperatures, ultimately producing a novel high field polarized state, with two distinct sublattices. New time-of-flight neutron scattering techniques, accompanied by large angular access, high magnetic field infrastructure allow the mapping of a sequence of ferromagnetic and incommensurate phases and their accompanying spin excitations. At least one of the transitions to incommensurate phases at μ0Hc1∼6.25 T and μ0Hc2∼7 T is discontinuous, while the final quantum critical point at μ0Hc3∼13 T is continuous.