Single-Step Synthesis of An Ideal Chain Antiferromagnet [H(4,4'-bipyridyl)](HO)FeF with Spin S=5/2.

One-dimensional (1D) magnets are of great interest owing to their intriguing quantum phenomena and potential application in quantum computing. We successfully synthesized an ideal antiferromagnetic spin S=5/2 chain compound [H(4,4'-bpy)](HO)FeF (4,4'-bpy=4,4'-bipyridyl) 1, using a single-step low-temperature hydrothermal method under conditions that favors the protonation of the bulky bidentate ligand 4,4'-bpy. Compound 1 consists of well-separated (Fe-F-) chains with a large Fe-F-Fe angle of 174.

Analogous Chain Selenite Chlorides BaM(SeO)Cl (M = Cu, Ni, Co, Mn) and PbCu(SeO)Cl with Tunable Spin : Syntheses and Characterizations.

A series of analogous chain selenite chlorides BaM(SeO)Cl (M = Cu , Ni , Co , Mn ) and PbCu(SeO)Cl with tunable spin from = 1/2 to = 5/2 have been hydrothermally synthesized and characterized. These analogues crystallized in the orthorhombic space group (monoclinic 2/ space group for ) all containing M-SeO-M spin chains, which are further separated by the Ba ions (Pb for ). The magnetic susceptibility results of , , and show broad maxima around 80.

Construction of Ideal One-Dimensional Spin Chains by Topochemical Dehydration/Rehydration Route.

One-dimensional (1D) Heisenberg antiferromagnets are of great interest due to their intriguing quantum phenomena. However, the experimental realization of such systems with large spin remains challenging because even weak interchain interactions induce long-range ordering. In this study, we present an ideal 1D = 5/2 spin chain antiferromagnet achieved through a multistep topochemical route involving dehydration and rehydration.

KMnO(OH)(VO)(VO) with Sawtooth Chains of Multivalent Manganese Triangular Trimer Units: Magnetic Susceptibility Shrouding a Long-Range Antiferromagnetic Order of Ferromagnetic Triangles.

-Pyrovanadate (or -diorthovanadate) KMnMnO(OH)(VO)(VO) synthesized hydrothermally crystallizes in the orthorhombic space group with = 17.9155(5), = 5.8940(2), = 10.

Successive short- and long-range magnetic ordering in rosiaite-type CoGeTeO prepared by ion-exchange reaction.

The missing member of the rosiaite family, CoGeTeO, was synthesized by mild ion-exchange reactions and characterized by magnetization and specific heat measurements. It exhibits a successive short- and long-range magnetic ordering at ≈ 45 K and = 15 K, respectively. Based on these measurements, the magnetic - phase diagram was established, showing two antiferromagnetic phases separated by a spin-flop transition.

Magnetic transitions of hydrogenated HCrO(= 0-2) monolayer from a ferromagnetic half-metal to antiferromagnetic insulator.

Two-dimensional (2D) transition metal oxide monolayers are currently attracting great interest in materials research due to their versatility and tunable electronic and magnetic properties. In this study, we report the prediction of magnetic phase changes in HCrO(0 ⩽⩽ 2) monolayer on the basis of first-principles calculations. As the H adsorption concentrationincreases from 0 to 0.

Successive Short- and Long-Range Magnetic Ordering in BaMn(SeO) with Honeycomb Layers of Mn Ions Alternating with Triangular Layers of Mn Ions.

Mixed-valent BaMnMn(SeO) crystallizes in a monoclinic structure and has honeycomb layers of Mn ions alternating with triangular layers of Mn ions. We established the key parameters governing its magnetic structure by magnetization and specific heat measurements. The title compound exhibits a close succession of a short-range correlation order at = 10.

Highly anisotropic 1/3-magnetization plateau in a ferrimagnet CsCu(SeO)·2HO: topology of magnetic bonding necessary for magnetization plateau.

We prepared CsCu(SeO)·2HO composed of Cu ions at square-planar coordination sites and characterized its structural and magnetic properties, to show that CsCu(SeO)·2HO is a ferrimagnet exhibiting a highly anisotropic 1/3-magnetization plateau. This unprecedented anisotropy in a magnetization plateau is the consequence of three effects, namely, the orthogonal arrangements of the corner-sharing CuO square planes, the nearest-neighbour antiferromagnetic exchange, and the anisotropic -factor of the Cu ions at square-planar coordination sites. By analyzing the topology of magnetic bonding, we found why magnetic plateaus are observed only for certain ferrimagnets and antiferromagnets.

Skin-Deep Aspect of Thermopower in BiQ, PbQ, and BiCuQO (Q = Se, Te): Hidden One-Dimensional Character of Their Band Edges Leading to High Thermopower.

ConspectusThermoelectric (TE) materials have received much attention because of their ability to convert heat energy to electrical energy. At a given temperature , the efficiency of a TE material for this energy conversion is measured by the figure of merit , which is related to the thermopower (or Seebeck coefficient) , the thermal conductivity κ, and the electrical conductivity σ of the TE material as = (σ)/κ. BiQ and PbQ (Q = Se, Te) are efficient TE materials with high , although they are not ecofriendly and their stability is poor at high temperature.

High-Spin Orbital Interactions Across van der Waals Gaps Controlling the Interlayer Ferromagnetism in van der Waals Ferromagnets.

We examined what interactions control the sign and strength of the interlayer coupling in van der Waals ferromagnets such as FeGeTe, CrGeTe, CrI, and VI to find that high-spin orbital interactions across the van der Waals gaps are a key to understanding their ferromagnetism. Interlayer ferromagnetic coupling in FeGeTe, CrGeTe, and CrI is governed by the high-spin two-orbital two-electron destabilization, but that in VI by the high-spin four-orbital two-electron stabilization. These interactions explain a number of seemingly puzzling observations in van der Waals ferromagnets.

Material research from the viewpoint of functional motifs.

As early as 2001, the need for the 'functional motif theory' was pointed out, to assist the rational design of functional materials. The properties of materials are determined by their functional motifs and how they are arranged in the materials. Uncovering functional motifs and their arrangements is crucial in understanding the properties of materials and rationally designing new materials of desired properties.

Magnetic Properties of ANiTeO (A = K, Li): Zigzag Order in the Honeycomb Layers of Ni Ions Induced by First and Third Nearest-Neighbor Spin Exchanges.

The static and dynamic magnetic properties and the specific heat of KNiTeO and LiNiTeO were examined and it was found that they undergo a long-range ordering at = 22.8 and 24.4 K, respectively, but exhibit a strong short-range order.

Spin-Peierls Distortion of TiPO Causing a Transition from a Magnetic to a Nonmagnetic Insulating State and Its Effect on the Thermoelectric Properties: Density Functional Theory Analysis.

Density functional theory calculations were carried out to probe the nature of the electronic structure change in TiPO before and after its spin-Peierls distortion at 74.5 K, which is characterized by the dimerization in the chains of Ti (d) ions present in TiPO. These calculations suggest strongly that the electronic state of TiPO is magnetic insulating before the distortion, but becomes nonmagnetic insulating after the distortion.

Microscopic Mechanism of the Heat-Induced Blueshift in Phosphors and a Logarithmic Energy Dependence on the Nearest Dopant-Vacancy Distance.

Heat-induced blueshift (HIB) observed in many luminescent materials is a puzzling phenomenon that has remained unexplained for decades. By using the high-throughput first-principles calculations and energy-screening techniques, we generated a number of model structures for five phosphors, RbLi[Li SiO ] :Eu , Na[Li SiO ]:Eu , K[Li SiO ]:Eu , Sr[LiAl N ]:Eu , and Ca[LiAl N ]:Eu . Our analyses suggest, to a first approximation, a logarithmic energy dependence on the nearest distance between the dopant and the metal-cation vacancy.

Structure and Origin of the Second-Harmonic Generation Response of Nonlinear Optical Material SrBeBO.

SrBeBO (SBBO) has long been considered as one of the most promising deep-ultraviolet nonlinear optical materials, but its crystal structure described by space group 6̅2 in previous studies has remained questionable. On the basis of first-principles calculations coupled with the high-throughput crystal structure prediction method, we found three energetically favorable structures for SBBO with space groups , , and 6̅. These structures and a superstructure of space group -S derived from the structure were refined by the Rietveld method using the available powder X-ray diffraction data.

In Honor of John Bannister Goodenough, an Outstanding Visionary.

John B [...

Factors Governing the Propagation Direction and Spin-Rotation Plane of Noncollinear Magnetic Structures: A Helix vs Cycloid in Doubly Ordered Perovskites NaYMnWO and NaYNiWO.

The magnetic structure of NaYMnWO was determined by neutron powder diffraction measurements. Below 9 K, the magnetic structure is a helix to wave vector = (0, 0.447, /), in contrast with NaYNiWO, which shows a transverse spin density wave with = (0.

Unusual Spin Exchanges Mediated by the Molecular Anion PS: Theoretical Analyses of the Magnetic Ground States, Magnetic Anisotropy and Spin Exchanges of MPS (M = Mn, Fe, Co, Ni).

We examined the magnetic ground states, the preferred spin orientations and the spin exchanges of four layered phases MPS (M = Mn, Fe, Co, Ni) by first principles density functional theory plus onsite repulsion (DFT + U) calculations. The magnetic ground states predicted for MPS by DFT + U calculations using their optimized crystal structures are in agreement with experiment for M = Mn, Co and Ni, but not for FePS. DFT + U calculations including spin-orbit coupling correctly predict the observed spin orientations for FePS, CoPS and NiPS, but not for MnPS.

Spin Hamiltonians in Magnets: Theories and Computations.

The effective spin Hamiltonian method has drawn considerable attention for its power to explain and predict magnetic properties in various intriguing materials. In this review, we summarize different types of interactions between spins (hereafter, spin interactions, for short) that may be used in effective spin Hamiltonians as well as the various methods of computing the interaction parameters. A detailed discussion about the merits and possible pitfalls of each technique of computing interaction parameters is provided.

Spin Exchanges Between Transition Metal Ions Governed by the Ligand p-Orbitals in Their Magnetic Orbitals.

In this review on spin exchanges, written to provide guidelines useful for finding the spin lattice relevant for any given magnetic solid, we discuss how the values of spin exchanges in transition metal magnetic compounds are quantitatively determined from electronic structure calculations, which electronic factors control whether a spin exchange is antiferromagnetic or ferromagnetic, and how these factors are related to the geometrical parameters of the spin exchange path. In an extended solid containing transition metal magnetic ions, each metal ion M is surrounded with main-group ligands L to form an ML polyhedron (typically, n = 3-6), and the unpaired spins of M are represented by the singly-occupied d-states (i.e.

Orbital Magnetic Moments of the High-Spin Co Ions at Axially-Elongated Octahedral Sites: Unquenched as Reported from Experiment or Quenched as Predicted by Theory?

Neutron diffraction studies on magnetic solids composed of axially elongated CoOX (X = Cl, Br, S, Se) octahedra show that the ordered magnetic moments of their high-spin Co (d, = /) ions are greater than 3 μ, i.e., the spin moment expected for = / ions, and increase almost linearly from 3.

On Ferro- and Antiferro-Spin-Density Waves Describing the Incommensurate Magnetic Structure of NaYNiWO.

The incommensurate magnetic structure (0.47, 0, 0.49) of NaYNiWO exhibits unconventional spin-density waves (SDWs) along the [100] direction, in which up and down spins alternate in each half-wave.

The partition principles for atomic-scale structures and their physical properties: application to the nonlinear optical crystal material KBeBOF.

In implementing the materials genome approach to search for new materials with interesting properties or functions, it is necessary to find the correct functional motif. To this end, it is common to partition an extended structure into various building units and then partition its properties to find the appropriate functional motif. We have developed the general principles for partitioning a structure and its properties in terms of a set of atoms and bonds by analyzing the differential cross-sections of neutron and X-ray scattering phenomena and proposed the procedures with which to partition an extended structure and its properties.

Aggregation of Polybismuthide Anions in a Single Compound Using Rh-CO Units: Heterometallic Cluster Ions [Rh@Bi(RhCO)] and [Rh@Bi(RhCO)].

In the presence of the roughly flat sequestering agent, [K(18-crown-6)], the reaction of Rh(CO)Cl with KBi in ethylenediamine () solution at room temperature yielded the heterometallic cluster anion [Rh@Bi(RhCO)] (), in which two hitherto unknown Bi building blocks (i.e., Bi crown and Bi pyramid) were stabilized by six Rh-CO units.