6 research outputs found
Quantum gapped state in a spin-1/2 distorted honeycomb-based lattice with frustration
We successfully synthesized (-Py-V)[Cu(hfac)], a verdazyl-based
complex. Molecular orbital calculations revealed five types of intermolecular
interactions between the radical spins and two types of intramolecular
interactions between the radical and the Cu spins, resulting in a spin-1/2
distorted honeycomb-based lattice. Additionally, competing ferromagnetic and
antiferromagnetic (AF) interactions induce frustration. The magnetization curve
displayed a multistage increase, including a zero-field energy gap. Considering
the stronger AF interactions that form dimers and tetramers, the magnetic
susceptibility and magnetization curves were qualitatively explained. These
findings demonstrated that the quantum state, based on the dominant AF
interactions, was stabilized due to the effects of frustration in the lattice.
Hence, the exchange interactions forming two-dimensional couplings decoupled,
reducing energy loss caused by frustration and leading to frustration-induced
dimensional reduction.Comment: 6 pages, 5 figure
Field-induced quantum phase in a frustrated zigzag-square lattice
This study presents the experimental realization of a spin-1/2 zigzag-square
lattice in a verdazyl-based complex, namely
(-Py-V-2,6-F)Cu(hfac). Molecular orbital calculations suggest
the presence of five types of frustrated exchange couplings. Our observations
reveal an incremental increase in the magnetization curve beyond a critical
field, signifying a phase transition from the antiferromagnetic ordered state
to a quantum state characterized by a 1/2 plateau. This intriguing behavior
arises from the effective stabilization of a zigzag chain by the external
fields. These results provide evidence for field-induced dimensional reduction
in a zigzag-square lattice attributed to the effects of frustration.Comment: 5 pages, 4 figure
Synthesis and Characterization of High-Entropy-Alloy-Type Layered Telluride MBi2Te4 (M = Ag, In, Sn, Pb, Bi)
Recently, high-entropy alloys (HEAs) and HEA-type compounds have been extensively studied in the fields of material science and engineering. In this article, we report on the synthesis of a layered system MBi2Te4 where the M site possesses low-, middle-, and high-entropy states. The samples with M = Pb, Ag1/3Pb1/3Bi1/3, and Ag1/5In1/5Sn1/5Pb1/5Bi1/5 were newly synthesized and the crystal structure was examined by synchrotron X-ray diffraction and Rietveld refinement. We found that the M-Te2 distance was systematically compressed with decreasing lattice constants, where the configurational entropy of mixing at the M site is also systematically increased. The details of structural refinements and the electrical transport property are presented
Mechanochemical Synthesis and Characterization of Metastable Hexagonal Li<sub>4</sub>SnS<sub>4</sub> Solid Electrolyte
A new crystalline
lithium-ion conducting material, Li<sub>4</sub>SnS<sub>4</sub> with
an <i>ortho</i>-composition, was prepared
by a mechanochemical technique and subsequent heat treatment. Synchrotron
X-ray powder diffraction was used to analyze the crystal structure,
revealing a space group of <i>P</i>6<sub>3</sub>/<i>mmc</i> and cell parameters of <i>a</i> = 4.01254(4)
Ã… and <i>c</i> = 6.39076(8) Ã…. Analysis of a heat-treated
hexagonal Li<sub>4</sub>SnS<sub>4</sub> sample revealed that both
lithium and tin occupied either of two adjacent tetrahedral sites,
resulting in fractional occupation of the tetrahedral site (Li, 0.375;
Sn, 0.125). The heat-treated hexagonal Li<sub>4</sub>SnS<sub>4</sub> had an ionic conductivity of 1.1 × 10<sup>–4</sup> S
cm<sup>–1</sup> at room temperature and a conduction activation
energy of 32 kJ mol<sup>–1</sup>. Moreover, the heat-treated
Li<sub>4</sub>SnS<sub>4</sub> exhibited a higher chemical stability
in air than the Li<sub>3</sub>PS<sub>4</sub> glass-ceramic
Magnetizing lead-free halide double perovskites
Spintronics holds great potential for next-generation high-speed and low-power consumption information technology. Recently, lead halide perovskites (LHPs), which have gained great success in optoelectronics, also show interesting magnetic properties. However, the spin-related properties in LHPs originate from the spin-orbit coupling of Pb, limiting further development of these materials in spintronics. Here, we demonstrate a new generation of halide perovskites, by alloying magnetic elements into optoelectronic double perovskites, which provide rich chemical and structural diversities to host different magnetic elements. In our iron-alloyed double perovskite, Cs2Ag(Bi:Fe)Br-6, Fe3+ replaces Bi3+ and forms FeBr6 clusters that homogenously distribute throughout the double perovskite crystals. We observe a strong temperature-dependent magnetic response at temperatures below 30 K, which is tentatively attributed to a weak ferromagnetic or antiferromagnetic response from localized regions. We anticipate that this work will stimulate future efforts in exploring this simple yet efficient approach to develop new spintronic materials based on lead-free double perovskites.Funding Agencies|Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [KAW 2019.0082]; Swedish Energy AgencySwedish Energy Agency [2018004357, P43288-1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Grant Agency of the Czech RepublicGrant Agency of the Czech Republic [GA19-05259S]; China Scholarship Council (CSC)China Scholarship Council; U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering DivisionUnited States Department of Energy (DOE); European CommunityEuropean Community (EC) [312284]; Czech Ministry of EducationMinistry of Education, Youth & Sports - Czech Republic [LM2015057]; CERIC users grant; International Synchrotron Access Program of the Australian Synchrotron</p