Magnetization Process of theS=1/2and 1 Ferrimagnetic Chain and Dimer

Fractional magnetization plateaus of the spin-12Heisenberg orthogonal-dimer chain: Strong-coupling approach developed from the exactly solved Ising-Heisenberg model

“…At the boundary the ground state is macroscopically degenerate where each dimer can be in any of two states singlet or triplet. We rewrite the Hamiltonian in terms of the projection operators (7) and perform the many-body perturbation theory (17) to get the following effective Hamiltonian up to second order terms:…”

“…From the experimental point of view, the fractional plateaux have been detected in magnetization curves of a variety of insulating magnetic materials, which mostly provide real-world representatives of zero-dimensional Heisenberg spin clusters 4-10 , one-dimensional Heisenberg spin chains [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] or twodimensional Heisenberg spin lattices [28][29][30][31][32][33][34][35][36] . The fractional magnetization plateaux of onedimensional quantum Heisenberg chains should satisfy the quantization condition p(S u − m u ) ∈ Z (p is a period of the ground state, S u and m u are the total spin and total magnetization per elementary unit, Z is a set of the integer numbers), which has been derived by Oshikawa, Yamanaka, Affleck (OYA) by extending the Lieb-SchultzMattis theorem [37][38][39] .…”

Insights into Nature of Magnetization Plateaus of a Nickel Complex [Ni4(μ-CO3)2(aetpy)8](ClO4)4 from a Spin-1 Heisenberg Diamond Cluster

“…Naturally, the most comprehensively understood are nowadays rational magnetization plateaus of the simplest molecular materials, which consist of well isolated magnetic molecules involving just a few spin centers coupled through antiferromagnetic exchange interactions. High-field measurements performed at sufficiently low temperatures have for instance proved the presence of an intermediate magnetization plateau(s) for the dinuclear nickel complex {Ni 2 } as an experimental realization of the spin-1 Heisenberg dimer [29][30][31], the dinuclear nickel-copper complex {NiCu} as an experimental realization of the mixed spin-(1,1/2) Heisenberg dimer [32], the trinuclear copper {Cu 3 } and nickel {Ni 3 } complexes as experimental realizations of the spin-1/2 and spin-1 Heisenberg triangles [33][34][35], the oligonuclear compound {Mo 12 Ni 4 } as an experimental realization of the spin-1 Heisenberg tetrahedron [36][37][38][39], the pentanuclear copper complex {Cu 5 } as an experimental realization of the spin-1/2 Heisenberg hourglass cluster [40,41], the hexanuclear vanadium compounds {V 6 } as experimental realizations of two weakly coupled spin-1/2 Heisenberg triangles [42,43], the hexanuclear copper compounds {Cu 6 } as experimental realizations of the spin-1/2 Heisenberg edge-shared tetrahedra [44][45][46], etc.…”

Magnetic Study of an Anisotropic Mixed Spin-1/2 and Spin-1 Ising Model on a Square Lattice with the Uniaxial Crystal-field Anisotropy

“…The formulation of the LCA is based on the Gibbs-Bogolyubov variational principle that enables to obtain the Gibbs free energy in a self-consistent manner with other thermodynamic quantities. Moreover, this model can be viewed as a very useful model in connection with the assemblies of weakly interacting Ni-Cu alternating chains [4,5].…”