Modern theories of quantum magnetism predict exotic multipolar states in weakly interacting strongly frustrated spin-1/2 Heisenberg chains with ferromagnetic nearest neighbor (NN) inchain exchange in high magnetic fields. Experimentally these states remained elusive so far. Here we report strong indications of a magnetic field-induced nematic liquid arising above a field of ~13 T in the edge-sharing chain cuprate LiSbCuO4 ≡ LiCuSbO4. This interpretation is based on the observation of a field induced spin-gap in the measurements of the 7Li NMR spin relaxation rate T 1 −1 as well as a contrasting field-dependent power-law behavior of T 1 −1 vs. T and is further supported by static magnetization and ESR data. An underlying theoretical microscopic approach favoring a nematic scenario is based essentially on the NN XYZ exchange anisotropy within a model for frustrated spin-1/2 chains and is investigated by the DMRG technique. The employed exchange parameters are justified qualitatively by electronic structure calculations for LiCuSbO4.

Four mononuclear cobalt­(II) complexes with pseudo tetrahedral geometry were isolated with different counteranions; their structure solution reveals the molecular formula as [Co­(L1)4]­X2 [where L1 = thiourea (NH2CSNH2) and X = NO3 (1), Br (2), and I (3)] and [Co­(L1)4]­(SiF6) (4). The detailed analysis of direct-current (dc) magnetic data reveals a zero-field splitting (ZFS; D) with m S = ±3/2 as the ground levels (D < 0) for the four complexes. The magnitude of the ZFS parameter is larger, in absolute value, for 1 (D = −61.7 cm–1) than the other three complexes (−5.4, −5.1, and −12.2 cm–1 for 2–4, respectively). The sign of D for 1, 2, and 4 was unambiguously determined by X-band electron paramagnetic resonance (EPR) spectroscopy of the diluted samples (10%) at 5 K. For 3, the sign of D was naturally endorsed from the frequency-dependent out-of-phase signal (χM″) observed in the absence of an external dc magnetic field and confirmed by high-frequency EPR (70–600 GHz) experiments performed on a representative pure polycrystalline 3, which gave a quantitative D value of −5.10(7) cm–1. Further, the drastic changes in the spin Hamiltonian parameters and their related relaxation dynamics phenomena (of 2–4 compared to 1) were rationalized using ab initio complete-active-space self-consistent field/n-electron valence perturbation theory calculations. Calculations disclose that the anion-induced structural distortion observed in 2–4 leads to a nonfavorable overlap between the π orbital of cobalt­(II) and the π* orbital of the sulfur atom that reduces the overall |D| value in these complexes compared to 1. The present study demonstrates that not only the first but also the second coordination sphere significantly influences the magnitude of the ZFS parameters. Particularly, a reduction of D of up to ∼90% occurs (in 2–4 compared to 1) upon a simple variation of the counteranions and offers a viable approach to modulate ZFS in transition-metal-containing single-molecule magnets.

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Pd3Bi2S2 and Pd3Bi2Se2 have been successfully prepared in the form of nanoparticles with diameters of ∼50 nm by microwave-assisted modified polyol synthesis at low temperatures. The composition and morphology of the samples have been studied by means of powder X-ray diffraction as well as electron microscopy methods, including X-ray intensity mapping on the nanoscale. Superconducting properties of the as-prepared samples have been characterized by electrical resistivity measurements down to low temperatures (∼0.2 K). Deviations from the bulk metallic behavior originating from the submicrometer nature of the samples were registered for both phases. A significant critical-field enhancement up to 1.4 T, i.e., 4 times higher than the value of the bulk material, has been revealed for Pd3Bi2Se2. At the same time, the critical temperature is suppressed to 0.7 K from the bulk value of ∼1 K. A superconducting transition at 0.4 K has been observed in nanocrystalline Pd3Bi2S2. Here, a zero-temperature upper critical field of ∼0.5 T has been estimated. Further, spark plasma-sintered Pd3Bi2S2 and Pd3Bi2Se2 samples have been investigated. Their superconducting properties are found to lie between those of the bulk and nanosized samples.

The family of antiferromagnetic layered metal hexathiohypo diphosphates, M2P2S6 represents a versatile class of materials, particularly interesting for fundamental studies on magnetic properties in low dimensional structures, and yet exhibiting great potential for a broad variety of applications including catalysis, energy storage and conversion, and spintronics. In this work, three representatives of this family of 2D materials (M = Fe, Ni, and Mn) are exfoliated in the liquid phase under inert conditions and the nanosheet’s properties are studied in detail for different sizes of all three compounds. Centrifugation-based size selection is performed for this purpose. The exfoliability and structural integrity of the nanosheets is studied by statistical AFM and TEM measurements. Further, we report size and thickness dependent optical properties and spectroscopic metrics for the average material dimensions in dispersion, as well as the nanomaterials’ magnetic response using a combination of cryo-Raman and SQUID measurements. Finally, the material stability is studied semi-quantitatively, using time and temperature dependent extinction and absorbance spectroscopy, enabling the determination of the materials’ half-life, portion of reacted substance and the macroscopic activation energy for the degradation.

A series of three mononuclear pentagonal-bipyramidal V(III) complexes with the equatorial pentadentate N3O2 ligand (2,6-diacethylpyridinebis(benzoylhydrazone), H2DAPBH) in the different charge states (H2DAPBH0, HDAPBH1-, DAPBH2-) and various apical ligands (Cl-, CH3OH,...

To investigate the influence of the coordination geometry on the magnetization relaxation dynamics, two geometric isomers of a fivecoordinate low-spin Co(II) complex with the general molecular formula [Co(DPPE) 2 Cl]SnCl 3 (DPPE = diphenylphosphinoethane) were synthesized and structurally characterized. While one isomer has a square pyramidal geometry (Co-SP (1)), the other isomer figures a trigonal bipyramidal geometry (Co-TBP (2)). Both complexes were already reported elsewhere. The spin state of these complexes is unambiguously determined by detailed direct current (dc) magnetic data, X-band, and high-frequency EPR measurements. Slow relaxation of magnetization is commonly observed for systems with S > 1/2. However, both 1 and 2 show field-induced slow relaxation of magnetization. Especially 1 shows relaxation times up to τ = 35 ms at T = 1.8 K, which is much longer than the reported values for undiluted Co(II) low-spin monomers. In 2, the maximal field-induced relaxation time is suppressed to τ = 5 ms. We attribute this to the change in g-anisotropy, which is, in turn, correlated to the spatial arrangement of ligands (i.e., coordination geometry) around the Co(II) ions. Besides the detailed electronic structure of these complexes, the experimental observations are further corroborated by theoretical calculations.

The mechanistic investigations between Cu(II) and the anisotropic lanthanides (Ln(III)) are not much explored to date. This is due to the complicated energy spectrum which arises due to the orbital angular momentum of anisotropic lanthanides. Interestingly, the exchange coupling J in Ln(III)−Cu(II) systems was found to be antiferromagnetic for <4f 7 metal ions and ferromagnetic for ≥4f 7 metal ions, while the net magnitude of J Total strength gradually decreases moving from f 1 to f 13 . While this is established in several examples, the reason for this intriguing trend is not rationalized. In this article, we have taken up these challenging tasks by synthesizing a family of complexes with the general molecular formula [Cu 2 Ln(HL) 4 (NO 3 )](NO 3 ) 2 , where Ln = La (1 -La ), Ce (2 -Ce ), Pr (3 -Pr ), Gd (4 -Gd ), Tb (5 -Tb ), Dy (6 -Dy ), and Ho (7 -Ho ) and HL = C 15 H 15 N 1 O 3 ; (2methoxy-6-[(E)-2′-hydroxymethyl-phenyliminomethyl]-phenolate) is a monodeprotonated tridentate Schiff base ligand. Detailed dc magnetic susceptibility measurements performed for all the complexes reveal that the Cu(II) ion is coupled ferromagnetically to the respective Ln(III) ion, which has more than seven electrons in the 4f shell, while an antiferromagnetic coupling is witnessed if Ln(III) has less than seven electrons. The strength of the exchange coupling constant was quantitatively determined for representative complexes from the high-field/high-frequency electron paramagnetic resonance spectroscopy which follows the order of 4 -Gd (1.50(10) cm −1 ) > 5 -Tb (1.18(10) cm −1 ) > 6 -Dy (0.56(10) cm −1 based on the −