Quantum magnetism of S equal 5 by 2 highly frustrated spin

Abstract

The geometrically frustrated spin systems (GFSS) and low-dimensional quantum spin newlinesystems (LDQSS) show emergent quantum phenomena in diverse novel quantum states newlineand strange magnetic excitations. Studying the unusual states of matter in GFSS and newlineLDQSS is one of the fascinating areas of fundamental research in condensed matter newlinephysics. The combination of geometrical frustration in LDQSS is another persuasive newlinetheme. The S = 12 newlinefrustrated spin chain (FSC) model was theoretically solved by C. newlineK. Majumdar and D. K. Ghosh. Hence, it is named as MG spin chain model. The newlineanalytical quantum model is exactly solved for the ratio of the 2nd nearest neighbor (NN) newlineto 1st NN (and#945; = J2/J1) = 0.5, and the ground state is a singlet and fully gapped. The newlinenumerical results predict that the Kosterlitz Thouless transition separates the gapless newlinecommensurate phase and gapped phase when the value of and#945; = 0.241. The quantum newlinephase diagram for large spins of S = 32 newlineand S = 52 newlineis quite different from that of the S = newline12 newlineMG chain model. A new phase of matter called the quotfloating phasequot can be realized newlinein the S = 52 newlineFSC model when and#945; gt 0.4. The floating phase is a quasi-long-range order newline(LRO) ground state at T = 0 K with gapless excitations accompanied by incommensurate newlinecorrelations. While there is substantial progress on theoretical fronts in the class of FSC newlinemodels, there is not much progress on the realization of experimental behavior in the newlineactual materials. We have investigated two S = 52 newlineFSC systems with this motivation. The newlinesynthesized materials are Bi3FeMo2O12 (BFMO) and K3Fe(MoO4)2(Mo2O7) (KFMO), newlineand the brief details are reported below. newlineThe structure of BFMO consists of very well-separated, infinite S = 52 newlinefrustrated spin newlinechains running along c-axis. Observing a broad maximum around 10 K in the magnetic newlinesusceptibility and#967;(T) suggests low-dimensional nature due to short-range spin correlations. newlineand#967;(T) data does not fit the S = 52 newlineuniform spin chain model due to the presence of dominant newline2nd nearest-neighbor (NN) coupling (J2) along with the 1s