Application of the finite-temperature Lanczos method for the evaluation of magnetocaloric properties of large magnetic molecules

Schnack, Jürgen; Heesing, Christian

doi:10.1140/epjb/e2012-30546-7

Cited by 20 publications

(17 citation statements)

References 33 publications

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“…It is well known that a steep variation of the magnetization at low magnetic fields points to a possible applicability for low-temperature magnetic refrigeration achieved through the enhanced magnetocaloric effect [68][69][70]. Considering this statement, the studied mixed-spin double-tetrahedral chain represents a quite good theoretical tool for a rigorous examination of the aforementioned phenomenon when the particle content is changed.…”

Section: Discussionmentioning

confidence: 96%

Magnetization plateau as a result of the uniform and gradual electron doping in a coupled spin-electron double-tetrahedral chain

Gálisová

2017

Phys. Rev. E

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The double-tetrahedral chain in a longitudinal magnetic field, whose nodal lattice sites occupied by the localized Ising spins regularly alternate with triangular plaquettes with the dynamics described by the Hubbard model, is rigorously investigated. It is demonstrated that the uniform change of electron concentration controlled by the chemical potential in a combination with the competition between model parameters and the external magnetic field leads to the formation of one chiral and seven non-chiral phases at the absolute zero temperature. Rational plateaux at onethird and one-half of the saturation magnetization can also be identified in the low-temperature magnetization curves. On the other hand, the gradual electron doping results in eleven different ground-state regions which distinguish from each other by the evolution of the electron distribution during this process. Several doping-dependent magnetization plateaux are observed in the magnetization process as a result of the continuous change of electron content in the model.

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Section: Discussionmentioning

confidence: 96%

Magnetization plateau as a result of the uniform and gradual electron doping in a coupled spin-electron double-tetrahedral chain

Gálisová

2017

Phys. Rev. E

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“…Our future goal is to extend a validity of the localized-magnon approach down to zero field, because a steep variation of the magnetization at low magnetic fields is of great potential applicability for low-temperature magnetic refrigeration achieved through the enhanced magnetocaloric effect. [76][77][78][79]…”

Section: Discussionmentioning

confidence: 99%

Diversity of quantum ground states and quantum phase transitions of a spin- 12 Heisenberg octahedral chain

et al. 2017

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The spin- 2Heisenberg octahedral chain with regularly alternating monomeric and squareplaquette sites is investigated using various analytical and numerical methods: variational technique, localized-magnon approach, exact diagonalization (ED) and density-matrix renormalization group (DMRG) method. The model belongs to the class of flat-band systems and it has a rich ground-state phase diagram including phases with spontaneously broken translational symmetry. Moreover, it exhibits an anomalous low-temperature thermodynamics close to continuous or discontinuous fielddriven quantum phase transitions between three quantum ferrimagnetic phases, tetramer-hexamer phase, monomer-tetramer phase, localized-magnon phase and two different spin-liquid phases. If the intra-plaquette coupling is at least twice as strong as the monomer-plaquette coupling, the variational method furnishes a rigorous proof of the monomer-tetramer ground state in a low-field region and the localized-magnon approach provides an exact evidence of a single magnon trapped at each square plaquette in a high-field region. In the rest of parameter space we have numerically studied the ground-state phase diagram and magnetization process using DMRG and ED methods. It is shown that the zero-temperature magnetization curve may involve up to four intermediate plateaus at zero, one-fifth, two-fifth and three-fifth of the saturation magnetization, while the specific heat exhibits a striking low-temperature peak in a vicinity of discontinuous quantum phase transitions.

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“…We investigated magnetic observables for several orien- The case where the applied field points along the uniaxial anisotropies can be treated with a FTLM code where the Hilbert space is decomposed into subspaces H(M ), compare [27,28]. The resulting effective magnetic moment is depicted by solid curves in Fig.…”

Section: Application To Large Spin Systemsmentioning

confidence: 99%

Advanced finite-temperature Lanczos method for anisotropic spin systems

Hanebaum

Schnack

2014

Eur. Phys. J. B

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It is virtually impossible to evaluate the magnetic properties of large anisotropic magnetic molecules numerically exactly due to the huge Hilbert space dimensions as well as due to the absence of symmetries. Here we propose to advance the Finite-Temperature Lanczos Method (FTLM) to the case of single-ion anisotropy. The main obstacle, namely the loss of the spin rotational symmetry about the field axis, can be overcome by choosing symmetry related random vectors for the approximate evaluation of the partition function. We demonstrate that now thermodynamic functions for anisotropic magnetic molecules of unprecedented size can be evaluated.

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Application of the finite-temperature Lanczos method for the evaluation of magnetocaloric properties of large magnetic molecules

Cited by 20 publications

References 33 publications

Magnetization plateau as a result of the uniform and gradual electron doping in a coupled spin-electron double-tetrahedral chain

Magnetization plateau as a result of the uniform and gradual electron doping in a coupled spin-electron double-tetrahedral chain

Diversity of quantum ground states and quantum phase transitions of a spin- 12 Heisenberg octahedral chain

Advanced finite-temperature Lanczos method for anisotropic spin systems

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