Crystal structure, Chemical Bonding, and Magnetism of α-FeGa: How Local Interactions Shape the Structure and Properties of Intermetallic Compounds.

α-FeGa was synthesized from the elements as a polycrystalline powder. Its crystal structure was redetermined by high-resolution powder X-ray diffraction, which showed a complex monoclinic structure of the FeGe type. The determined lattice parameters ( = 10.

MnGaS and MnAlSe van der Waals Chalcogenides: A Source of Atomically Thin Nanomaterials.

Layered chalcogenides containing 3d transition metals are promising for the development of two-dimensional nanomaterials with interesting magnetic properties. Both mechanical and solution-based exfoliation of atomically thin layers is possible due to the low-energy van der Waals bonds. In this paper, we present the synthesis and crystal structures of the MnGaS and MnAlSe layered chalcogenides.

Bulk ferromagnetism in cleavable van der Waals telluride NbFeTe.

A van der Waals telluride, NbFeTe, has been synthesized using chemical vapor transport reactions. The optimized synthetic conditions yield high-quality single crystals with a novel monoclinic crystal structure. Monoclinic NbFeTe demonstrates a (100) cleavage plane, bulk ferromagnetism below 87 K, and a metallic ground state-the necessary prerequisites for needed spintronics technologies.

Impact of Ge Doping on Structural and Magnetic Ordering in RMnGa and RMnGaGe (R = Tb, Dy; ≤ 0.25, ≈ 1.0-3.3).

Single crystals of RMnGa and their new quaternary derivatives RMnGaGe (R = Tb, Dy, ≤ 0.25, ≈ 1.0-3.

Itinerant ferromagnet ReMnGe ( = 0.9-1.5, = 0.42-0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure.

ReMnGe ( = 0.9-1.5, = 0.

Layered van der Waals Chalcogenides FeAlSe, MnAlS, and MnAlSe: Atomically Thin Triangular Arrangement of Transition-Metal Atoms.

Layered van der Waals (vdW) chalcogenides of 3d transition metals are a rich source of two-dimensional (2D) nanomaterials, in which atomically thin layers with the terminating chalcogen atoms exhibit promising functionality for novel spintronic devices. Here, we report on the synthesis, crystal growth, and magnetic properties of FeAlSe, MnAlS, and MnAlSe ternary chalcogenides. Crystal structures are probed by powder X-ray diffraction, Mössbauer spectroscopy, and high-resolution transmission electron microscopy.

Cleavable crystals, crystal structure, and magnetic properties of the NbFeTe layered van der Waals telluride.

Transition metal-based two-dimensional nanomaterials with competing magnetic states are at the cutting edge of spintronic and low-power memory devices. In this paper, we present a Fe-rich NbFeTe layered telluride ( ≈ 0.5), which shows an interplay of spin-glass and antiferromagnetic states below the Néel temperature of 179 K.

Fe-Rich Ferromagnetic Cleavable Van der Waals Telluride FeAsTe.

Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride FeAsTe can be synthesized by the high-temperature reaction of elements.

Ferromagnetic correlations in the layered van der Waals sulfide FeAlS.

Transition metal-based layered compounds with van der Waals gaps between the adjacent layers are a source of two-dimensional (2D) nanomaterials with nontrivial transport and magnetic properties. 2D ferromagnets, both metals and semiconductors, can be leveraged to produce spin-polarized current in spintronic devices with tailored functionalities. Here, we report on the synthesis, crystal growth, crystal and electronic structure, and magnetic properties of the Fe-based FeAlS layered sulfide.

Semiconducting and Metallic Compounds within the IrIn Structure Type: Stability and Chemical Bonding.

Narrow-gap semiconductors are very rare among intermetallic compounds. They appear only when two factors come together: strong hybridization of valence orbitals in the vicinity of the Fermi level and an appropriate number of valence electrons. Surprisingly, the IrIn family of intermetallics contains a number of semiconductors, including 17 e FeGa, RuGa, OsGa, and RuIn, for which the d-p hybridization gap opens at the Fermi energy.

Intermetallic Compound ReGaGe with Re- and Ge-Embedded Gallium Clusters: Synthesis, Crystal Structure, Chemical Bonding, and Physical Properties.

Transition metal-based endohedral cluster intermetallic compounds are interesting electron phases, which frequently exhibit superconductivity with a peculiar interplay between the critical temperature and valence electron count. We present a new Re-based endohedral gallium cluster compound, ReGaGe. Its unique crystal structure (4 space group, = 8.

Endohedral cluster intermetallic superconductors: at the frontier between chemistry and physics.

When a transition metal combines with an excess of a p-metal, the latter forms endohedral clusters with the number of vertices up to 14. These clusters are the building units of endohedral cluster intermetallic compounds. Although discovered a few decades ago, they have gained renewed interest due to their peculiar crystal and electronic structures and frequently observed superconducting properties.

Magnetic structures of FeGeAs and FeGeP intermetallic compounds: a neutron diffraction and Fe Mössbauer spectroscopy study.

FeGeAs and FeGeP are quasi-binary intermetallic compounds that possess a rare variant of intergrowth-type crystal structure, which is a combination of the column shaped CoAl and MgFeGe structure type blocks. The compounds are antiferromagnets with the Néel temperatures around 125 K. Neutron powder diffraction experiments on the samples with δ≈ 0.

Electron-Precise Semiconducting ReGaGe: Extending the IrIn Structure Type to Group 7 of the Periodic Table.

Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGaGe, a new electron-precise narrow-gap intermetallic semiconductor. The compound crystallizes in the IrIn structure type (space group 4/, = 6.

Endohedral Cluster Superconductors in the Mo-Ga-Sn System Explored by the Joint Flux Technique.

Endohedral Ga cluster compounds feature nontrivial superconducting states including the two-gap superconductivity similar in nature to MgB. We use the joint flux synthetic technique to introduce Sn into the Ga matrix and tune the valence electron count in the two new endohedral cluster superconductors MoGaSn and MoGaSn with critical temperatures of = 8.7 and 5.

Single-gap superconductivity in MoGa.

In this paper, the potential existence of two-gap superconductivity in MoGa is addressed in detail by means of thermodynamic and spectroscopic measurements. A combination of highly sensitive bulk and surface probes, specifically ac-calorimetry and scanning tunneling spectroscopy (STS), are utilized on the same piece of crystal and reveal the presence of only one intrinsic gap in the system featuring strong electron-phonon coupling. Minute traces of additional superconducting phases detected by STS and also in the heat capacity measured in high magnetic fields on a high-quality and seemingly single-phase crystal might mimic the multigap superconductivity of MoGa suggested recently in several studies.

From endohedral cluster superconductors to approximant phases: synthesis, crystal and electronic structure, and physical properties of MoGaZn and MoGaZn.

Using the crystal-growth joint flux technique based on the combination of two aliovalent low-melt metals, gallium and zinc, we adjust the gross valence electron count in the Mo-Ga-Zn system and produce the MoGaZn and MoGaZn intermetallic compounds. Gradual reduction in the valence electron count first leads to the Zn for Ga substitution in the MoGa endohedral cluster superconductor, accompanied by the formation of Zn-containing clusters in the crystal structure and by the gradual suppression of superconductivity. MoGaZn with x = 7.

ReGaGe: an intermetallic compound with semiconducting properties and localized bonding.

ReGaGe2 is a new member of the family of intermetallic compounds with non-metallic properties. It displays highly localized covalent bonding patterns. Its electronic structure is governed by mixing of Re d orbitals with the s and p orbitals of Ga and Ge and features the Fermi level falling into the opened band gap, ensuring experimentally confirmed semiconducting properties.

ReGaGe: Intermetallic Compound with Pronounced Covalency in the Bonding Pattern.

We report synthesis, crystal and electronic structure, and transport properties of new intermetallic compound ReGaGe, which was obtained by two-step ampule method from the elements. ReGaGe crystallizes in its own structure type (space group I4/ mmm, a = 2.89222(3) Å, c = 15.

Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count.

In this study, we modify the flux-growth method for the purpose of exploratory synthesis of ternary intermetallic compounds. Our concept is based on the assumption that valence electron count plays a crucial role in the stability of polar intermetallic compounds of different structure types. Control of the valence electron count parameter is made possible through the use of an excess of two metals having a different number of valence electrons.

Magnetism of coupled spin tetrahedra in ilinskite-type KCuO(SeO)Cl.

Synthesis, thermodynamic properties, and microscopic magnetic model of ilinskite-type KCuO(SeO)Cl built by corner-sharing Cu tetrahedra are reported, and relevant magnetostructural correlations are discussed. Quasi-one-dimensional magnetic behavior with the short-range order around 50 K is rationalized in terms of weakly coupled spin ladders (tubes) having a complex topology formed upon fragmentation of the tetrahedral network. This fragmentation is rooted in the non-trivial effect of the SeO groups that render the Cu-O-Cu superexchange strongly ferromagnetic even at bridging angles exceeding 110°.

Effect of Transition Metal Substitution on the Structure and Properties of a Clathrate-Like Compound Eu₇CuAs.

A series of substitutional solid solutions-Eu₇CuTAs (T = Fe, Co, Ni)-based on a recently discovered clathrate-like compound (Eu₇CuAs) were synthesized from the elements at 800 °C. Almost up to 50% of Cu can be substituted by Ni, resulting in a linear decrease of the cubic unit cell parameter from = 16.6707(1) Å for the ternary compound to = 16.

Nontrivial Recurrent Intergrowth Structure and Unusual Magnetic Behavior of Intermetallic Compound FeGeAs.

A new phase FeGeAs (δ ≤ 0.136) was obtained by two-step synthesis from the elements. FeGeAs crystallizes in its own structure type (space group P6/mmm, Z = 1, a = 11.

Structural and Thermodynamic Stability of the "1111" Structure Type: A Case Study of the EuFZnPn Series.

Two new compounds with the LaOAgS structure, EuFZnAs (1) and EuFZnSb (2), were obtained via solid state reaction. Both compounds are tetragonal (P4/nmm) with the cell parameters a = 4.1000(1) Å and c = 9.

New Fe-based layered telluride FeAsTe: synthesis, crystal structure and physical properties.

A new ternary telluride, FeAsTe, was synthesized from elements at 600 °C. It crystallizes in the hexagonal P6/mmc space group with the unit cell parameters a = 3.85091(9) Å and c = 17.