Quantum phase transitions and decoupling of magnetic sublattices in the quasi-two-dimensional Ising magnetCo3V2O8in a transverse magnetic field

Abstract

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.

Three-dimensional magnetism and the Dzyaloshinskii-Moriya interaction in S = 3/2 kagome staircase Co 3 V 2 O 8

“…This set of fitting parameters replicates the energy positions of the measured spin wave excitations in the lower energy branch (roughly between 1.5 and 2. . Further, this proposed Hamiltonian also replicates the measured spectra of the lower energy branch in previously reported data in the (H 0 L) scattering plane (22,25) and along the [0 K K/4 + 2.5] direction (26). There is, however, some discrepancy between the measured and simulated dispersion for the higher energy branch (roughly between 4 and 6 meV) particularly along the [0 0 L] direction.…”

“…A value of J 6 = 0.01 meV was chosen to lower this flat mode by a small amount so as to best match the observed data once the DM term was included. A previous work (25) had also suggested an antiferromagnetic J 6 because of an antiferromagnetic ordering pattern observed on the cross-tie sites with a 15-T magnetic field applied along the b axis. Given the symmetry relations of the DM interaction on the nearest-neighbor bond, shown in Fig.…”

Quasi-two-dimensional spin correlations in the triangular lattice bilayer spin glass LuCoGaO4

“…The Co 2+ moment then arises from the appropriate crystal field splitting of the L = 3, S = 3/2 Hund's rule ground state, which gives a Kramer's doublet corresponding to S eff = 1/2 after applying spin-orbit coupling, as is commonly the case in Co 2+ -based magnetic insulators. [32][33][34][35] These results are consistent with previous data from Cava et al obtained on powder samples. 12 The frustration index of f ∼ 5 indicates moderate frustration.…”

Quantum Ising model on the frustrated square lattice

“…Analogous phenomena have been observed in many materials [15], suggesting that our results can provide an interesting additional mechanism, based on competing interactions, for quantum annealed criticality. Underlying signatures of quantum phase transitions are often observed in the thermodynamics properties even at finite temperatures [1,25,26]. For instance, quantum criticality is usually associated with accumulation of entropy at low but nonzero temperatures [3,27].…”