The anhydrous alums as model triangular-lattice magnets

Abstract

We show that materials based on the yavapaiite layered structure are of potential interest as realizations of a model quasi-two-dimensional triangular-lattice antiferromagnet. The structure type is such that magnetic ions occupy a regular or very slightly distorted triangular lattice in well separated layers. We report the magnetic susceptibility versus temperature behaviour of three compounds: , which has an equilateral triangular lattice, and and which both have isosceles triangular lattices. A comparison of the behaviour of these three compounds identifies the effect of distortion and the spin value on the properties of the triangular-lattice antiferromagnet. , which we have made for the first time, has S = 1/2, and may prove to be the best example of the S = 1/2 triangular-lattice antiferromagnet yet discovered.

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)2

“…This behaviour is explainable only by the effect of frustration, which efficiently suppresses the growth of antiferromagnetic correlation. Similar behaviour has been found in κ-(BEDT-TTF) 2 Cu 2 (CN) 3 [4] and a few other materials [7][8][9]. Most Z [Pd(dmit) 2 ] 2 salts exhibit antiferromagnetic ordering at lower temperatures [2], while no magnetic phase transition is detected in κ-(BEDT-TTF) 2 Cu 2 (CN) 3 down to very low temperatures, which is viewed as the first evidence for a gapless spin-liquid state realised in κ-(BEDT-TTF) 2 Cu 2 (CN) 3 [4].…”

Critical behavior of two-dimensional frustrated spin models with noncollinear order

“…The critical behavior of the Heisenberg frustrated antiferromagnet is clearer; many experiments [31] agree with theoretical predictions based on topological considerations [32][33][34], Monte Carlo simulations [32,33,[35][36][37][38]27], the application of appropriate N Lσ models [39][40][41][42][43] and by the use of ERG [44]. The order parameter space of this model is the group of 3D rotations, in fact O(3)/Z 2 ≡ SO(3) ≡ P 3 [32].…”

Geometrically Frustrated Magnetic Materials

“…The Ti material on the other hand does not order above 1.2 K and shows f > 10, which should provide motivation for further studies. [28,29] An additional set of distorted TP magnets is provided by another form of site-ordered NaCl oxide, namely, A 5 MO 6 . Two examples which have been studied in some detail are Li 4 MgReO 6 and Li 5 OsO 6 .…”