Quantum magnetoelectric effect in the molecular crystal Dy3

Abstract

Magnetoelectric properties of a molecular crystal formed by dysprosium triangular clusters are investigated. The effective spin-electric Hamiltonian is derived on the base of developed quantum mechanical model of the cluster spin structure. The magnetoelectric contribution to the free energy of the crystal is calculated. The analysis reveals several distinctive features of the magnetoelectric effect, which are not typical for conventional paramagnetic systems at low temperatures. The peculiarities are explained by the chirality of the dysprosium core of the molecules. PACS numbers: 75.85.+t -Magnetoelectric effects, multiferroics; 75.45.+j -Macroscopic quantum phenomena in magnetic systems arXiv:1108.1460v1 [cond-mat.mes-hall]

Coupling Dy3 Triangles to Maximize the Toroidal Moment

“…For example, concepts such as magnetism, magnetocaloric effects, and ferroelectrics can be viewed as properties recognizable at the condensed as well as molecular level, and there is growing interest in exploring the boundaries between these two worlds. [6] The recently investigated Dy 3 triangle (prototype Dy 3 ) [7] is one of the four possible ingredients for creating multiferroic systems that should manifest two or more out of ferroelectric, ferromagnetic, ferroelastic, and ferrotoroidal behavior. [2b, 5] On the other hand, it can also be difficult to separate purely molecular-based effects from those resulting from a resultant toroidal moment arising through a long-range interaction.…”

“…[10] Dy 3 Cu is constructed by combining alternating trinuclear Dy 3 SMM-building blocks and enantiopure, chiral copper(II) complexes. [6,12] The toroidal ground spin state structure analysis of the Dy 3 Cu system reveals that the combination of molecular chirality and the toroidal magnetism are predicted to provide multiferroic behavior only under applied fields. [7,11] This system not only shows an essentially nonmagnetic spin ground state but also possesses a toroidal moment as described above and SMM behavior deriving from its excited states.…”

Single-Molecule Toroics and Multinuclear Lanthanide Single-Molecule Magnets

“…4.2 [5]. Further investigations of the magnetoelectric properties revealed specific magnetoelectric and magneto-current effects of this compound related to its toroidal moment [7]. Therefore, by analogy with SMMs, we can call those molecular clusters as single-molecule toroics (SMTs) [8].…”

“…Finally, as a significant step to final applications, the magnetoelectric properties for the above Dy 3 molecule were also explored, suggesting that an external magnetic field is able to induce the electric polarization in the crystal (Fig. 4.3) [7]. Therefore, lanthanide coordination complexes with toroidal magnetic moment might be good candidates to observe the macroscopic quantum magnetoelectric effects and other peculiar spin-electric effects.…”

“…The most typical example is the triangular Dy 3 SMM reported in 2006, showing the non-magnetic ground state due to the toroidal arrangement of anisotropic axes, which opens up the research field of multinuclear lanthanide SMMs [4]. Significantly, a new concept of single-molecule toroic (SMT) was put forward on the basis of the toroidal magnetic moments of ground doublets present in the cyclic lanthanide SMMs [7,8].…”