A pseudo-spin model for poly(vinylidene fluoride-trifluoroethylene) copolymers

Magnetic properties of the spin‐1/2 Ising–Heisenberg diamond chain with the four‐spin interaction

“…Of course, the immense theoretical interest to the spin models with multispin interactions is not purposeless. Multispin interactions have been experimentally observed in real triangular magnetic systems composed of 3 He atoms absorbed on graphite surfaces [10], the hydrogen bonded ferroelectrics PbHPO 4 and PbDPO 4 [11], as well as, the squaric acid crystal (H 2 C 2 O 4 ) [12,13,14] and some copolymers [15]. Recently, it was shown that the cyclic four-spin interaction could also explain the neutron-scattering experiments concerning high-T c compounds such as La 2 CuO 4 [16], La 6 Ca 8 Cu 24 O 41 [17,18], and La 4 Sr 10 Cu 24 O 41 [19].…”

Monte Carlo investigation of the mixed spin Ising model with four-spin interaction and next-nearest neighbor couplings

“…The models with pair and quartet interaction have been applied successfully to study and explain the existence of first order phase transition in squaric acid crystal H 2 C 2 O 4 [21]. Such models have been also used to describe thermodynamical properties of hydrogen-bonded ferroelectric PbHPO 4 , PbDPO 4 [22], some copolymers [23] and optical conductivity [24] observed in cuprate ladder La x Ca 14-X Cu 24 [25,26] and La 4 Sr 10 Cu 24 O 41 [27] reveal that they could be explained by the introduction of the four-spin interaction. It is worthy to note here that this later plays an important role in the two dimensional antiferromagnet La 2 CuO 2 [28], the parent material of high-T C superconductors.…”

Frustration in an exactly solvable mixed-spin Ising model with bilinear and three-site four-spin interactions on a decorated square lattice

“…On the other hand, from the experimental point of view, the models with multispin interactions have been widely used to explain the thermodynamic properties of various physical systems, such as binary alloys [23], classical fluids [31], solid He 3 [32], lipid bilayers [33], metamagnets [34], rare gases [35] or hydrogen bonded ferroelectrics PbHPO 4 and PbDPO 4 [36]. One should also mention here that the models with multispin interactions have been successfully used to describe the first-order phase transition in the squaric acid crystal H 2 C 2 O 4 [27,37,38] and some co-polymers [39]. Moreover, the cycling four-spin exchange interactions have been adopted to explain experimental results on spin gaps [40]- [42], Raman peaks [43] and optical conductivity of the cuprate ladder La 2 Ca 14−x Cu 24 O 41 [44].…”