Magnetic states of coupled spin tubes with frustrated geometry in CsCrF4

Abstract

When a theoretical model is realized in nature, small perturbation terms play important roles in the selection of the ground state in geometrically frustrated magnets. In case of a triangular spin tube, the two-dimensional network of the inter-tube interaction forms characteristic lattices. Among them Kagome-Triangular (KT) lattice is known to exhibit an enriched phase diagram including various types of non-trivial structures: non-coplanar cuboc structure, coplanar 120°structure with the two-dimensional propagation vector of k 2D = (0, 0), ffiffi ffi 3 p ffiffi ffi 3 p structure with k 2D = (1/3, 1/3), and incommensurate structure. We investigate the magnetic state in the model material CsCrF 4 by using neutron diffraction technique. Combination of representation analysis and Rietveld refinement reveals that a very rare structure, i.e., a quasi-120°structure with k 2D = (1/2, 0), is realized at the base temperature. The classical calculation of the phase diagram elucidates that CsCrF 4 is the first experimental realization of the KT lattice having ferromagnetic Kagome bond. A single-ion anisotropy and Dzyaloshinskii-Moriya interaction play key roles in the selection of the ground state. Furthermore, a successive phase transition having an intermediate state represented by k 2D = (1/3, 1/3) is observed. The intermediate state is a partially ordered 120°structure which is induced by thermal fluctuation.

Dehydration of Electrochemically Protonated Oxide: SrCoO2 with Square Spin Tubes

“…SrCoO 2 has square (or four-legged) spin tubes ( S = 3/2) and offers an interesting perspective on spin ladder physics. Quantum spin ladders have been intensively studied because of their relevance to high- T c superconductivity , and the existence of distinct ground states between odd- and even-legged ladders. , Later, spin tubes imposing a periodic boundary condition in the rung direction were investigated, with experimental correspondences of three-legged tubes (e.g., CsCrF 4 ) , and nine-legged ones (Na 2 V 3 O 7 ) . For even-legged tubes, only a 1D chain compound Cu 2 Cl 4 ·H 8 C 4 SO 2 has been proposed as topologically equivalent .…”

Large magnetic anisotropy of a decorated spin-chain system K2Co3(MoO4)3(OH)2

“…Among these exotic materials, 2-D magnetic lattices including stripe Kagome and triangular stripe layers, and 1-D triangular spin chains such as sawtooth chains, half sawtooth chains, and triangular spin tubes are of particular interest because of their intriguing magnetic properties. [10][11][12][13][14][15][16][17][18] Competition between first, second, and third nearest neighbor magnetic exchange interactions often leads to rich magnetic phase diagrams of these materials. Moreover, these materials provide a platform to study the effect of the change of lattice dimensionality with different arrangements of the basic triangular magnetic building unit.…”

Inelastic neutron scattering in the weakly coupled triangular spin tube candidate CsCrF4

“…In an asymmetric triangular spin tube where Z 2 symmetry is broken, the spin gap is suppressed, and Tomonaga-Luttinger liquid (TLL) with vector chiral order is predicted [9,10]. In contrast with the accumulative theoretical studies, experimental study has been limited to an S = 3/2 spin tube candidate CsCrF 4 [11][12][13][14][15][16] for lack of a model material.…”