Chemistry Department and the Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, ON, Canada K1N 6N5.
Published: December 2011
AI Article Synopsis
Article Abstract
A dysprosium(III) sandwich complex, [Dy(III)(COT″)(2)Li(THF)(DME)], was synthesized using 1,4-bis(trimethylsilyl)cyclooctatetraenyl dianion (COT″). The complex behaves as a single-ion magnet and demonstrates unusual multiple relaxation modes. The observed relaxation pathways strongly depend on the applied static dc fields.
We enhance single-ion magnet (SIM) magnetisation reversal barriers by engineering the second coordination sphere, substituting conventional small monoanions with a bulky polyoxometalate (POM) trianion. Importantly, our approach serves as a model for creating new high-performance multifunctional hybrid materials.
Experimental results on two supramolecular complexes in which a Cr or Fe d-orbital single-ion magnet center is embedded between a pair of Fe spin-crossover moieties make those two complexes interesting as possible candidates for use in quantum information technologies. We report detailed computational results for their structure and electronic properties and use the resulting data to parametrize a spin Hamiltonian that facilitates comparison with experimental results and their interpretation. Consistent with experimental results on decoherence in [Fe(ox)]@[FeL], we find it to be easy-plane type while the [Cr(ox)]@[FeL] system is easy-axis type.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) is a promising technique to achieve cryogenic temperature. However, magnetic entropy change (Δ), the driving force of ADR, remains far below theoretical -Δ = ln(2 + 1)/ for most magnetic refrigerants. Here, we report giant MCE in orthorhombic EuCl, where a ferromagnetic ground state with excellent single-ion behavior of Eu and free spins has been demonstrated by combining calculations with Brillouin function analysis and magnetic measurements.
Noncoplanar magnets are excellent candidates for spintronics. However, such materials are difficult to find, and even more so to intentionally design. Here, we report a chemical design strategy that allows us to find a series of noncoplanar magnets-LnSn (Ln = Dy, Tb)-by targeting layered materials that have decoupled magnetic sublattices with dissimilar single-ion anisotropies and combining those with a square-net topological semimetal sublattice.
This work reports the engineering and functional properties of an emerging class of heterobimetallic 3d-4f ionic complexes designed with cobalt and rare-earth (RE) metals. We present a comprehensive examination of the structural, magnetic, optical, and thermal properties of the heterobimetallic ionic complexes with the general formula [Co(hfa)][RE(hfa)tetraglyme] (RE = Dy, Eu, and Y), where the metal centres are coordinated by hexafluoroacetylacetonate (Hhfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione), β-diketone and tetraglyme (2,5,8,11,14-pentaoxapentadecane) polyether. Structural analysis reveals an octahedral coordination geometry enveloping the cobalt(II) centre, characterized by inherent symmetry properties consistent across the derivatives, while a capped square-antiprism coordination polyhedron is observed for the RE ions.
