Research on the Structural and Magnetic Phase Transitions of CeMnGe Alloy.

Magnetic phase transitions play crucial roles in various material applications, including sensors, actuators, information storage, magnetic refrigeration, and so on. Typically, these magnetic phase transitions exhibit discontinuous first-order phase transitions. When a material undergoes a magnetic phase transition, it often exhibits simultaneous changes in both its crystal and electronic structures.

TiFeCO.

The phase with composition TiFeCO, tetra-titanium diiron carbide oxide, was unexpectedly synthesized by high-pressure sinter-ing (HPS) of a stoichiometric mixture with nominal composition TiFe. The TiFeCO phase crystallizes in the space group and can be considered as the TiFe structure filled with C and O atoms co-occupying the same octa-hedral void [occupancy ratio 0.82 (7):0.

Crystal structure of TiNiC.

Single crystals of the inter-metallic phase with composition TiNiC were serendipitously obtained by high-pressure sinter-ing of a mixture with initial chemical composition TiNi. The TiNiC phase crystallizes in the space group and can be considered as a partially filled TiNi structure with the C atom occupying an octa-hedral void. TiNiC is isotypic with TiNiO, NbNiC and TaNiC, all of which were studied previously by means of powder diffraction.

Crystal structure of AlFe.

Three B2-type inter-metallic AlFe phases (0.18 < δ < 0.05) in the Al-Fe binary system were synthesized by smelting and high temperature sinter-ing methods.

AlCuFe.

The inter-metallic phase with composition AlCuFe was synthesized by high-temperature sinter-ing of a mixture with initial chemical composition AlCuFe. AlCuFe adopts the CsCl structure type in space-group . The structure analysis revealed that one site is co-occupied by Al and Cu with a ratio of 0.

Electron Density Changes and Ultrafast Carrier Dynamics of the Antiferromagnetic Semiconductor MnPS through Magnetic Phase Transition.

Studying ultrafast dynamics provides us with a way to modify materials from the timescale of particle interaction, and the related research on antiferromagnetic semiconductors is still inadequate. Based on the electron density reconstruction, we achieve the visualization of magnetic interactions of bulk antiferromagnetic MnPS in the ground state, reveal the role of two atomic site occupations of S atoms in different magnetic phase transitions, and provide the theoretical and experimental support for modifying magnetic properties by selectively replacing the S atom. The ultrafast carrier dynamics can provide information from the excited state to the ground state.

Natural djurleite with refined composition CuS revealing disorder of some Cu sites.

A djurleite crystal was discovered from a natural sample originally labelled as chalcocite. The djurleite crystal under investigation has a refined composition of CuS, thus revealing a Cu deficiency compared to the originally reported CuS phase [Evans (1979). , 299-320], where all atomic sites are reported to be fully occupied.

The AlMnNi phase in the Al-Mn-Ni system.

An inter-metallic phase in the Al-Mn-Ni system crystallizing in space group (No. 63) and refined formula AlMnNi (called the ' phase) has been synthesized by high-temperature sinter-ing of a mixture with initial chemical composition AlMnNi. In comparison with the structure model of the previously reported phase with composition AlMnNi [Robinson (1954 ▸).

observation of the electrochemical lithiation of a single MnO@C nanorod electrode with core/shell structure.

Transition metal oxides (TMOs) play a crucial role in lithium-ion batteries (LIBs) due to their high theoretical capacity, natural abundance, and benign environmental impact, but they suffer from limitations such as cyclability and high-rate discharge ability. One leading cause is the lithiation-induced volume expansion (LIVE) for "conversion"-type TMOs, which can result in high stress, fracture and pulverization. Using carbon layers is an effective strategy to provide effective volumetric accommodation for lithium-ion (Li) insertion; however, the detailed mechanism is unknown.

Discovery of Dome-Shaped Superconducting Phase and Anisotropic Transport in a van der Waals Layered Candidate NbIrTe under Pressure.

The unique electronic structure and crystal structure driven by external pressure in transition metal tellurides (TMTs) can host unconventional quantum states. Here, the discovery of pressure-induced phase transition at ≈2 GPa, and dome-shaped superconducting phase emerged in van der Waals layered NbIrTe is reported. The highest critical temperature (T ) is ≈5.

Crystal structure of the AlMnNi phase in the Al-Mn-Ni system.

The inter-metallic phase with composition AlMnNi (icosa-aluminium penta-manganese nickel) was synthesized by high-temperature sinter-ing of a mixture with initial chemical composition AlMnNi. AlMnNi adopts the CoAl structure type in space-group type 6/, replacing the Co atoms with the transition-metal atoms Mn and Ni. Structure analysis revealed that one of the two transition-metal sites is partially occupied by Ni [refined occupancy 0.

The structure of the aluminium-abundant γ-brass-type AlMn.

An aluminium-abundant AlMn/γ-brass-type inter-metallic with formula AlMn, which is isotypic with γ-AlCr and γ-AlV, was discovered by high-temperature sinter-ing of an Al/Mn mixture with initial composition AlMn. Structure analysis revealed that one special position (Wyckoff site 18 in space group ) is shared by Al and Mn, with refined site occupancy factors of 0.7 and 0.

Effective Regulation of ZnO Surface Facets for Enhanced Photoluminescence Properties Assisted by Zinc Quaternary Ammonium Salts.

Novel ZnO twined-mushroom structures highly exposed in (001̅) planes were fabricated via a facile solvothermal synthesis with assistance of a zinc quaternary ammonium salt in the methanol-water solvent to show enhanced photoluminescence properties. A series of ZnO morphologies regulated with different surface facets were obtained in both MeOH-HO and EtOH MeOH-HO solvents respectively, tuning the proportion of alcohol. The self-aggregation mechanism was proposed based on the time-controlled experiment to evaluate the formation of twined-mushroom structures.

Large Anisotropic Magnetocaloric Effect, Wide Operating Temperature Range, and Large Refrigeration Capacity in Single-Crystal MnGe and MnGe/MnFeGe Heterostructures.

At present, the studies on magnetocaloric properties are mainly based on polycrystalline materials, which is not enough to reveal and understand the origin of their magnetocaloric effect. In addition, finding new room temperature magnetocaloric materials is crucial to the development and application for room temperature magnetic refrigeration. Here, we report the magnetic transitions, magnetic anisotropy, and magnetocaloric properties of single-crystal MnGe and MnGe/MnFeGe heterostructures with six (100) surfaces and the [001] growth direction prepared using the Sn flux method.

Crystal structure of AlCr, a phase closely related to the η-phase in the binary Al-Cr system.

The monoclinic η-phase in the binary Al-Cr system was initially named by Bradley & Lu [Bradley & Lu (1937 ▸). . , 319-337] as having the composition AlCr (Al:Cr ratio = 5.

Crystal structure of the AlCr-type inter-metallic AlCr.

An aluminium-deficient AlCr-type inter-metallic with formula AlCr (octa-aluminium penta-chromium) was uncovered when high-pressure sinter-ing of a mixture with composition AlCr was carried out. Structure analysis reveals that there are three co-occupied positions with refined occupancy factors for Al atoms being 0.958, 0.

Colossal Negative Linear Compressibility in Porous Organic Salts.

Negative linear compressibility (NLC) is a common sense violation (that is, crystal phases expand in one or more directions under hydrostatic compression). The excellent NLC performance of crystal materials is intrinsically related to the geometric structure of its skeleton. Here, we discovered a crystalline porous organic salt (CPOS-1); high-pressure X-ray diffraction experiments reveal that the CPOS-1 shows colossal NLC ( = -90.

Liquid Exfibration and Optoelectronic Devices of Fibrous Phosphorus.

Quasi-one-dimensional (Q1D) semiconductor materials, such as carbon nanotubes, SbSI, MP (M = Li, Na, K), and selenium and tellurium nanowires, show amazing potential for applications in future nanoelectronic and optoelectronic devices. However, intricate chirality in the structure of carbon nanotubes limits their applications. Also, the performance of MP in optoelectronics has yet to be extensively explored.

First-principles investigation of novel polymorphs of Mg2C.

On the basis of the evolutionary methodology for crystal structure prediction, the potential crystal structures of magnesium carbide with a chemical composition of Mg2C are explored. Except the known cubic phase (Fm3̅m), two novel tetragonal structures (P42/mnm and I41/Amd) and two novel hexagonal structures (P63/mmc and P6̅M2) of Mg2C are found. All these four new phases are mechanically and dynamically stable by the calculated elastic constants and phonon dispersions.

Rich stoichiometries of stable Ca-Bi system: structure prediction and superconductivity.

Using a variable-composition ab initio evolutionary algorithm implemented in the USPEX code, we have performed a systematic search for stable compounds in the Ca-Bi system at different pressures. In addition to the well-known tI12-Ca2Bi and oS12-CaBi2, a few more structures were found by our calculations, among which phase transitions were also predicted in Ca2Bi (tI12 → oI12 → hP6), Ca3Bi2 (hP5 → mC20 → aP5) and CaBi (tI2 → tI8), as well as a new phase (Ca3Bi) with a cF4 structure. All the newly predicted structures can be both dynamically and thermodynamically stable with increasing pressure.

Novel metastable compounds in the Zr-B system: an ab initio evolutionary study.

Using ab initio evolutionary simulations, we have explored the potential crystal structures with up to 18 atoms in the unit cell for all possible stoichiometries of the Zr-B system. In addition to the reported ZrB, ZrB2, ZrB12, oP8-ZrB and Zr3B4, two extraordinary Zr2B3 and Zr3B2 have been found to be both mechanically and dynamically stable, as verified by the calculated elastic constants and phonon dispersions. The calculated formation enthalpies reveal that both the new phases may be synthesized and found in experiments.

A novel stable binary BeB₂ phase [corrected].

Potential crystal structures of BeB2 were explored using ab initio evolutionary simulations. A new phase with a Cmcm space group was uncovered. It was determined that the Cmcm phase is mechanically and dynamically stable and has a lower enthalpy, from ambient pressure up to 13 GPa, than any previously proposed phases, as measured using first-principles calculations.

Phase transitions, mechanical properties and electronic structures of novel boron phases under high-pressure: a first-principles study.

We have explored the mechanical properties, electronic structures and phase transition behaviors of three designed new phases for element boron from ambient condition to high-pressure of 120 GPa including (1) a C2/c symmetric structure (m-B₁₆); (2) a symmetric structure (c-B₅₆) and (3) a Pmna symmetric structure (o-B₂₄ ). The calculation of the elastic constants and phonon dispersions shows that the phases are of mechanical and dynamic stability. The m-B₁₆ phase is found to transform into another new phase (the o-B₁₆ phase) when pressure exceeds 68 GPa.