Quantum Phase Transitions and De-Coupling of Magnetic Sublattices in the Quasi-Two Dimensional Ising Magnet Co3V2O8 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, Co$_3$V$_2$O$_8$, 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 allows 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 $\mu_0H_{c1}\sim6.25$ T and $\mu_0H_{c2}\sim7$ T are discontinuous, while the final quantum critical point at $\mu_0H_{c3}\sim 13$ T is continuous.