Antiperovskite Compounds Research Articles

The structural, electronic and magnetic properties of [formula omitted] anti-perovskite

A comprehensive exploration of the structural, electronic, and magnetic attributes of anti-perovskite Fe3ZnC carbides was carried out using Density Functional Theory (DFT) and Monte Carlo Simulation (MCS). These anti-perovskite materials possess a unique structure where cation and anion positions are interchanged within the perovskite framework. Our study involves a comparative analysis of the electronic band structures and density of states (DOS) for Fe3ZnC, considering prior theoretical and experimental research. Understanding these anti-perovskite materials' band structures and DOS is pivotal for their effective utilization in magnetic sensors and magnetic refrigeration applications. Our results indicate that Fe3ZnC displays ferromagnetic metallic behavior, particularly when applying the Generalized Gradient Approximation (GGA). Notably, there is a significant overlap between the valence (VB) and conduction (CB) bands. Furthermore, MCS predicts a second-order ferromagnetic-to-paramagnetic transition in the anti-perovskite Fe3ZnC compound, characterized by a notably high Curie temperature. These insights advance our understanding of these materials, paving the way for their effective utilization in magnetic technologies.

Two New Energetic Hexagonal Anti-Perovskites (N2H5)3X[B12H12] · H2O (X− = [NO3]− and [ClO4]−): Crystal Structure, Vibrational Spectra, and Thermal Decomposition

Two novel energetic anti-perovskite compounds with the chemical formula (N2H5)3X[B12H12] · H2O, where X− is either [NO3]− or [ClO4]−, were successfully synthesized. Both dodecahydro-closo-dodecaborates crystallize orthorhombically in the space group Cmc21, exhibiting relatively similar lattice parameters ((N2H5)3[NO3][B12H12] · H2O: a = 915.94(5), b = 1817.45(9), c = 952.67(5) pm, (N2H5)3[ClO4][B12H12] · H2O: a = 1040.51(6), b = 1757.68(9), c = 942.34(5) pm both for Z = 4). Their synthesis involved a two-step process: first, Cs2[B12H12] passed through a cation exchange column to yield the acidic form of the dodecahydro-closo-dodecaborate, (H3O)2[B12H12]. This aqueous solution was subsequently neutralized with hydrazinium hydroxide and mixed with the corresponding water-dissolved hydrazinium salt (nitrate or perchlorate). Characterization of the obtained crystals was performed by single-crystal X-ray diffraction and Raman spectroscopy as well as thermal analyses (TG-DTA and DSC). The crystal structure determinations revealed that both compounds adopt a hexagonal anti-perovskite structure, distorted by the presence of water molecules. These compounds containing oxidizing oxoanions demonstrate a remarkable ability to release large amounts of energy (almost 2100 J/g) upon thermal decomposition.

Synthesis and Characterization of High-Energy Anti-Perovskite Compounds Cs3X[B12H12] Based on Cesium Dodecahydro-Closo-Borate with Molecular Oxoanions (X- = [NO3]-, [ClO3]- and [ClO4]-).

Three novel anti-perovskite compounds, formulated as Cs3X[B12H12] (X- = [NO3]-, [ClO3]-, and [ClO4]-), were successfully synthesized through the direct mixing of aqueous solutions containing Cs2[B12H12] and CsX (X-: [NO3]-, [ClO3]-, [ClO4]-), followed by isothermal evaporation. All three compounds crystallize in the orthorhombic space group Pnma, exhibiting relatively similar unit-cell parameters (e.g., Cs3[ClO3][B12H12]: a = 841.25(5) pm, b = 1070.31(6) pm, c = 1776.84(9) pm). The crystal structures were determined using single-crystal X-ray diffraction, revealing a distorted hexagonal anti-perovskite order for each. Thermal analysis indicated that the placing oxidizing anions X- into the 3 Cs+ + [B12H12]2- blend leads to a reduction in the thermal stability of the resulting anti-perovskites Cs3X[B12H12] as compared to pure Cs2[B12H12], so thermal decomposition commences at lower temperatures, ranging from 320 to 440 °C. Remarkably, the examination of the energy release through DSC studies revealed that these compounds are capable of setting free a substantial amount of energy, up to 2000 J/g, upon their structural collapse under an inert-gas atmosphere (N2). These three compounds represent pioneering members of the first ever anti-perovskite high-energy compounds based on hydro-closo-borates.

Unlocking the chemical space in anti-perovskite conductors by incorporating anion rotation dynamics

Anti-perovskite compounds have drawn significant research interest as promising next-generation electrolytes for solid-state batteries, due to the high chemical stability against Li-metal, the negligible electronic conductivity and low cost. However, the low ionic conductivity, and the deficient fundamental understandings of ion transports impede the further optimization of the lithium anti-perovskite electrolytes. Herein, we reveal that exchanging anion lattice sites in the anti-perovskite could promote the structure stabilities and ionic conductivities simultaneously, by incorporating the rotational dynamics of anion clusters and strengthening the coupling between Li migrations and cluster rotations. Based on high-throughput calculations by density functional theory (DFT), twelve new anti-perovskite materials are predicted to exhibit superionic conductivity, among which the highest ionic conductivity of 10.9 mS/cm in Li3BrSO4 can be achieved (hundreds of times higher than the ionic conductivity of typical Li3OCl antiperovskite, 0.021 mS/cm). Furthermore, the local difference frequency center is proposed to quantitatively characterize the coupled degree of Li migration and cluster rotation, revealing the contribution of paddlewheel effect to the ionic conductivity. Our proposed cation-anion dynamics coupling in site-exchanged and cluster-based antiperovskites not only open a new avenue for understanding the key role played by rotational dynamics on fast lithium mobility, but also can be generally applied to develop other fast ionic conductors with cluster dynamics.

Ab initio study of structural, electronic, and optical properties of the anti-perovskite compound Na3OCN

This paper investigates the structural, electronic, and optical properties of the anti-perovskite compound Na3OCN for the first time. Calculations are performed using the first-principles density functional theory (DFT) within the generalized gradient approximation (GGA). The lattice parameters obtained from the optimal calculations are in relatively good agreement with the experimental data. The calculated electronic band structure and density of states (DOS) show a direct band gap of 2.76 eV which implies the semiconductor characteristics of this compound, an n-type semiconductor. The band gap decreases by applying the tensile or compressive strains to the compound. Moreover, the complex dielectric function of this compound is calculated. Then it is employed to obtain the other optical properties, such as absorption, reflectivity, refractive index, extinction coefficient, loss function, and optical conductivity, as a function of energy in the range of 0-35 eV. The results indicate that the applied strain can alter the optical band gap, absorption edge, and static values of the real part.

Critical Behavior of the Competing Magnetic Nature in the Antiperovskite Compound

Antiperovskite materials are deemed as a promising candidate for data storage and efficient energy conversion, exemplified by giant magnetoresistance (GMR) and magnetocaloric effect (MCE). In particular, the abundant magnetic configurations of antiperovskites endow them with a high degree of diversity in probing novel phenomena. Herein, we report the critical behavior of the antiperovskite Sn0.6NFe3.4 with an obvious second-order magnetic transition around Curie temperature (TC = 230 K). The obtained critical exponents (β, γ, and δ) are well consistent for different theoretical methods, which are also verified by the Widom scaling law and scaling equation. It is found that the critical exponent of β is much in accordance with the value of the mean-field model, indicating a long-range FM coupling in the system, whereas the other γ and δ are accessible to the three-dimensional (3D) Heisenberg model. Our work promotes the understanding of antiperovskite magnetism, providing insight for further fundamental research and resulting applications.

Magnetocaloric effect in Fe-based antiperovskite compound Sn0.6NFe3.4

Magnetocaloric effect in Fe-based antiperovskite compound Sn0.6NFe3.4

Effects of Fe doping on structure, negative thermal expansion, and magnetic properties of antiperovskite Mn3GaN compounds

AbstractWe synthesized antiperovskite Mn3Ga1−xFexN (0 ≤ x ≤ 0.30) compounds and investigated their negative thermal expansion (NTE) behavior, structure, and magnetic properties. A high‐resolution transmission electron microscopy analysis and a selected‐area electron diffraction (SAED) pattern indicate that the samples have high crystallinity with a single‐phase cubic structure. Tunable NTE behavior appears below room temperature, and the NTE operation temperature range (△T) is broadened while increasing the Fe doping. Furthermore, introducing Fe in Mn3Ga1−xFexN can efficiently adjust the NTE coefficient from −232.57 × 10−6/K (x = 0) to −12.57 × 10−6/K (x = 0.20), and the corresponding △T can be broadened from △T = 22 K to 51 K. Besides, the total entropy change (ΔStotal) at the phase transitions continuously decreases from 9.2 to 4.7 J/(kg K) while increasing the Fe content from x = 0.05 to 0.10. With increasing Fe into Ga sites, the magnetic ordering varies from antiferromagnetic (AFM) to ferromagnetic (FM), the AFM to paramagnetic (PM) phase transition temperature decreases, whereas the FM to PM transition temperature increases when increasing the Fe content. The present study indicates that magnetic element doping can efficiently tune the NTE and the correlated physical features of the antiperovskite compounds.

Elucidating Structure-Property Correlation in Perovskitoid and Antiperovskite Piperidinium Manganese Chloride.

In the world of semiconductors, organic-inorganic hybrid (OIH) halide perovskite is a new paradigm. Recently, a zealous effort has been made to design new lead-free perovskite-like OIH halides, such as perovskitoids and antiperovskites, for optoelectronic applications. In this context, we have synthesized a perovskitoid compound (Piperidinium)MnCl3 (compound 1) crystallizing in an orthorhombic structure with infinite one-dimensional (1D) chains of MnCl6 octahedra. Interestingly, this compound shows switchable dielectric property governed by an order-disorder structural transition. By controlling the stoichiometry of piperidine, we have synthesized an antiperovskite (Piperidinium)3Cl[MnCl4] (compound 2), the inverse analogue of a perovskite, consisting of zero-dimensional (0D) MnCl4 tetrahedra. This type of organic-inorganic hybrid antiperovskite halide is unique and scarce. Such a dissimilarity in lattice dimensionality and Mn2+ ion coordination ensues fascinating photophysical and magnetic properties. Compound 1 exhibits red emission with a photoluminescence quantum yield (PLQY) of ∼28%. On the other hand, the 0D antiperovskite compound 2 displays green emission with a higher PLQY of 54.5%, thanks to the confinement effect. In addition, the dimensionality of the compounds plays a vital role in the exchange interaction. As a result, compound 1 shows an antiferromagnetic ground state, whereas compound 2 is paramagnetic down to 1.8 K. This emerging structure-property relationship in OIH manganese halides will set the platform for designing new perovskites and antiperovskites.

Double Paddle‐Wheel Enhanced Sodium Ion Conduction in an Antiperovskite Solid Electrolyte (Adv. Energy Mater. 7/2023)

Solid State Electrolytes Solid-state conductors utilizing the rotation of atomic clusters to facilitate fast-ion transport provide an alternative mechanism to the classical picture of ion hopping through a fixed lattice. The antiperovskite compound Na2NH2BH4, described in article number 2203284 by Yet-Ming Chiang and co-workers, is an example where two such clusters work in concert to increase Na+ conduction.

Control of structural and magnetic transition in GeNCr3 by doping manganese ions

As an archetypal antiperovskite nitride compound, GeNCr3 undergoes a temperature-driven first-order antiferromagnetic-paramagnetic transition at approximately 418 K, accompanied with a structural phase transition from space group P-421m to I4/mcm. In this paper, we show that the critical temperature of GeNCr3 can be tuned from 418 to 240 K by doping manganese ions. Simultaneously, the evolution of the magnetic transition is consistent with the structural transition. Using temperature-dependent X-ray diffraction and X-ray photoelectron spectroscopy, in combination with first-principles calculations, we demonstrate that doping manganese ions tend to occupy the equatorial plane of the nitrogen octahedron.

Chiral magnetism, lattice dynamics, and anomalous Hall conductivity in V3AuN antiferromagnetic antiperovskite

Antiferromagnetic antiperovskites, where magnetically active $3d$ metal cations are placed in the octahedral corners of a perovskite structure, are in the spotlight due to their intertwined magnetic structure and topological properties. Especially their anomalous Hall conductivity, which can be controlled by applied strain and/or electric field, makes them highly attractive in different electronic applications. Here, we present the study and theoretical understanding of an antiperovskite compound that can offer enormous opportunities in a broad set of applications. Using first-principles calculations, we investigated the structure, lattice dynamics, noncollinear magnetic ordering, and electronic behavior in the vanadium-based antiperovskite ${\mathrm{V}}_{3}\mathrm{AuN}$. We found an antiperovskite structure centered on N similar to the ${\mathrm{Mn}}_{3}A\mathrm{N}$ family as the structural ground state. In such a phase, a $Pm\overline{3}m$ ground state was found in contrast to the Cmcm post-antiperovskite layered structure, as in the ${\mathrm{V}}_{3}A\mathrm{N}$, $A=\mathrm{Ga}$, Ge, As, and P. We studied the lattice dynamics and electronic properties, demonstrating its vibrational stability in the cubic structure and a chiral antiferromagnetic noncollinear ordering as a magnetic ground state. Finally, we found that the anomalous Hall conductivity, associated with the topological features induced by the magnetic symmetry, is ${\ensuremath{\sigma}}_{xy}=\ensuremath{-}291\phantom{\rule{4pt}{0ex}}\mathrm{S}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ $({\ensuremath{\sigma}}_{111}=\ensuremath{-}504\phantom{\rule{4pt}{0ex}}\mathrm{S}\phantom{\rule{0.16em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1})$. The latter is the largest reported in the antiferromagnetic antiperovskite family of compounds.

Sign reversal of the anomalous Hall effect in antiperovskite (110)-oriented Mn3.19Ga0.81N1−δ film

Antiperovskite compounds with abundant magnetic phase transitions provide an ideal platform for exploring nontrivial magnetotransport responses. In this study, the anomalous Hall effect (AHE) in an antiperovskite (110)-oriented Mn3.19Ga0.81N1−δ film up to room temperature was observed, and an unusual sign reversal was detected in the Hall measurements. The AHE reversal suggests that the carrier reversal corresponds to a magnetic transition from a ferrimagnetic order to noncollinear antiferromagnetic order at about 240 K. Analysis of the scaling relation of AHE indicates that the sign reversal originates from the transition from the skew scattering dominated AHE to the intrinsic mechanism dominated AHE. These findings will inspire effective control of the magnetic configuration and innovative applications for manipulating carrier transport in spintronic memory devices based on antiperovskite films.

Packing fraction induced phase separation in A-site doped antiperovskites

Local phase separation displayed by the A site doped Mn 3 Sn 1 − x A x C antiperovskites is investigated by studying a series of compounds wherein, the doped A site atoms inflicts changes in electronic contribution to the valence band while keeping the average size of the A site similar (In for Sn), or the size of the A-site atom is varied while maintaining the electronic density constant (Ge for Sn) or both, size and electronic density are varied (Zn for Sn). The study shows that the phase separation is a result of varied distortion of Mn 6 C octahedra due to the difference in the packing fractions of the unit cells. This distortions of the Mn 6 C octahedra are responsible for the observed magnetic properties of these antiperovskite compounds. • All A site substituted antiperovskite compounds, though have a cubic structure, display a local phase separation. • The Mn 6 C octahedra are distorted and the extent of distortion depends on the packing fraction of the unit cell. • Local phase separation and the distortions of the Mn 6 C octahedra play a decisive role in magnetic ground state of these antiperovskite compounds.

Limitations of scaling laws for determining the order of magnetic phase transitions in antiperovskite materials

For materials with magnetic phase transition, researchers have tried to find a simple magnetic method that can replace the calorimetric technique for determining the type of phase transition. Recently, the researchers provide a quantitative characteristic of first-order magnetic phase transitions, which is believed to have wide application prospect. The maximum exponent n, calculated from field dependence of magnetic entropy change, is>2 only for first-order phase transitions. This method has been tested in Bean-Rodbell model and for various types of materials with first-order phase transitions from ferromagnetic to paramagnetic or antiferromagnetic to ferromagnetic state. However, in this work, the determination of the order of phase transitions based on field dependence of magnetic entropy change contradicts the results of calorimetric measurements in antiperovskite compounds Mn3SnC and MnCu0.97N. This discrepancy may be associated with a first-order magnetic transition from ferrimagnetic to paramagnetic state in antiperovskite materials.

Electronic, magnetic, elastic and thermodynamic properties of antiperovskite metallic compounds Mn3XN (X = Ni, Pd, Pt): A DFT study

Antiperovskite compounds have been attracting a lot of attention because of their unique and remarkable properties. Although antiperovskite metallic compounds Mn3XN (X = Ni, Pd, Pt) have been successfully prepared as potential magnetic materials, the structural, electronic, elastic and thermodynamic properties are still unclear. So, in this work, we apply the first-principles calculations to investigate the physical properties of Mn3XN. The results of formation enthalpy show that Mn3XN compounds are thermodynamically stable and follow the order of Mn3NiN > Mn3PdN > Mn3PtN. The results of band structure and density of states prove that all Mn3XN compounds are magnetic metals and the magnetism of Mn3XN comes mainly from the contribution of Mn atoms. The calculated bulk modulus and shear modulus of Mn3PtN are bigger than the Mn3PdN and Mn3NiN. Especially, we give the three-dimensional Young's modulus surface and the projection surface on different planes for three compounds. With respect to the anisotropic characteristics, Mn3PdN may be a potentially isotropic material and Mn3NiN has the most obvious anisotropy. The sound velocities of the three compounds in different directions are calculated to obtain the Debye temperature. The Debye temperatures of Mn3NiN, Mn3PdN, Mn3PtN are calculated to be 445 K, 423 K and 408 K, respectively. Importantly, the Debye temperature increases with the increasing of pressure and the decreasing of temperature. Finally, we give the critical pressure and charge density difference of three compounds.

Antiperovskite Magnetic Materials with 2p Light Elements for Future Practical Applications

AbstractLight elements having 2p electrons such as B, C, and N are common elements that have played an important role in various functional materials. In particular, nitrides have long been used in the development of semiconductors, superconductors, and magnets. More recently, Fe‐ and Mn‐based antiperovskite‐type compounds with light elements have attracted considerable attention in the field of spintronic engineering, because of the development of intriguing and practical applications making them one of the key materials for future devices. In this article, it is first reviewed the evolution of applications and which light elements are employed. Then the representative applications and characteristics of the light elements, including magnetoresistive effects, magnetization switching, current‐spin and thermoelectric conversions, magnetic anisotropy, and domain nucleation are individually highlighted. Additionally, the crystal structure, fundamental properties, and theoretical study are addressed to enable a deeper understanding of the role of light elements in the unit cell. Beyond compounds with N, a demonstration using B and C is discussed to examine their effect on the magnetic structures of antiperovskite compounds. Finally, prospective and future strategies are discussed to build a platform of practical material based on light elements.

Elastocaloric-like effect in strain-mediated Mn3SnC/PZT magnetoelectric hetero-composite for solid-state refrigeration

Concerning the part of global warming caused by conventional refrigerant gasses, past decades of research on solid-state cooling technologies based on caloric effects present an attractive alternative with zero-greenhouse gas emission and higher operating efficiency. However, the search for materials with large caloric effects near room temperature has become a challenge in modern material physics. Mn-based antiperovskite compounds are favorable caloric materials which generate a reversible enthalpy change by applying an external field. We report a novel approach of piezo-enhanced elastocaloric-like effect on Mn3SnC for solid-state refrigeration application. In the as-designed Mn3SnC/PZT magnetoelectric hetero-composite, the reversible caloric effect of Mn3SnC was regulated by the electric field-induced strain in the PZT piezoelectricity layer without any external magnetic field. In addition, we proposed an experimental setup for the direct adiabatic temperature change measurement of the caloric effect. The adiabatic temperature change is as high as ∼ 0.57 K at 280 K under an electric field of 0.8 kV/cm, which is approximately 2 factors larger than that of the magnetocaloric effect value of Mn3SnC under 3 T. By adopting the first-principles theory, we estimated the entropy change is approximately 2.6 J Kg−1 K−1 at 280 K which is close to the previous reports. This work demonstrates a novel approach to effectively enhance reversible caloric effects in first-order phase transition materials via electric fields.

The effect of interface reaction on the thermal and mechanical properties of Mn3.2Zn0.5Sn0.3N/Al composites

The salient feature of low-expansion metal matrix composites is their dimensional stability. Due to the limitation of the performance of the reinforcement, the current low-expansion metal matrix composite materials cannot achieve both low expansion and high mechanical strength at the same time. With its extremely negative thermal expansion behavior and metallic characteristics, the anti-perovskite manganese nitrogen compound can be used as an ideal thermal expansion inhibitor to prepare high mechanical strength low-expansion composite materials. In the present work, fully-dense Mn3.2Zn0.5Sn0.3N/Al composites with low thermal expansion and high strength have been successfully fabricated by pressure infiltration. The effects of fabricating temperature on the microstructure, thermal expansion and mechanical properties of the Mn3.2Zn0.5Sn0.3N/Al composites have been discussed. Several interfacial reactions were caused by the high fabrication temperature (750 °C and 800 °C). Lower fabrication temperature (700 °C) was used to obtain a well-controlled interface composite with low thermal expansion (α = 6.5 × 10−6 K−1), high compression strength (481 MPa) and hardness (612 HV). A modified theoretical model has also been used to analyze the thermal expansion behavior of the composites.

Elastic anisotropies, electronic structures and tensile properties of anti-perovskite M3AlC (M=Ti, Co, Fe, Mn) phases: A first-principles calculation

Anti-perovskite material is a new functional material with excellent hydrogen storage and energy storage, which has great potential for reverse expansion. In this paper, the structural stability, mechanical properties, thermodynamic properties, electronic structure and tensile properties of M3AlC compounds were studied by using the first-principle calculation based on density functional theory. The results showed that the elastic modulus, sound velocity and minimum thermal conductivity of M3AlC are anisotropic, and the density of States and charge difference density showed that M3AlC compounds contain not only strong covalent bonds, but also metal bonds and ionic bonds. Mulliken population analyzed the overall bonding strength. Finally, the tensile strength of M3AlC compounds was also discussed. Which provide a theoretical framework for the further study of anti-perovskite material M3AlC compounds.