Anisotropic Physical Properties Research Articles

Anisotropy in elasticity and physical properties of Ti2B under high pressure

The anisotropic elasticity and physical properties of Ti2B with I4/m symmetry are predicted by the first-principle method combined with the quasi-harmonic Debye model. The effects of pressure on elastic constants, polycrystalline elastic moduli, Poisson’s ratio, Vickers hardness, and fracture toughness are calculated. The high pressure limit of mechanical stability of Ti2B is ∼70 GPa. The calculated polycrystalline elastic moduli B, G, E, and fracture toughness increase with pressure. The Vickers hardness decreases with pressure, but it is still relatively hard. The values of G/B and Poisson’s ratio indicate the ductility of Ti2B enhanced with the increase of pressure. The elastic anisotropy is investigated via the various anisotropic indexes (AU, AB, AG, A1, A2 and A3), 3D surface constructions and projections of bulk and Young’s moduli. The opposite effects of pressure and temperature on the isothermal bulk modulus, thermal expansion coefficient, heat capacity, Debye temperature, and Grüneisen parameter of Ti2B have been found.

Electric field assisted-unidirectional hybrid films of carbon nanotubes and liquid crystal polymer for light modulation

ABSTRACTTo develop stable polymer films which had high orientational ordering of carbon nanotube for polarization-dependent light modulator, we present a new concept for electric-field induced alignment of mesogenic carbon nanotubes (m-CNTs) in reactive mesogen host (RMS) fixed by ultraviolet (UV) polymerization. Covalent modification of m-CNTs was performed using structure-tailored mesogenic units [4-(6-hydroxyhexanolxy)-4’-carbonitrile, PCNOH] in esterification reaction based on 100–500 nm long CNTs shortened by acid oxidation cutting, confirmed through 1H NMR, FT-IR, Raman and XPS spectroscopy. Dynamic orientation of m-CNTs in soft m-CNT/RMS composite without aggregates was observed on a large scale by polarized optical microscopy, in which m-CNTs aligns along the electric field direction. It was reasonable the mesogenic segments introduced onto m-CNTs weakened van der walls interactions between the nanotubes by increasing steric repulsion, and then effectively improved the favourable affinity of m-CNTs with RMS molecules. Direct UV-induced polymerization of RMS molecules stabilized the orientational ordering of m-CNTs confirmed by Raman spectroscopy, and the obtained film also exhibited anisotropic light absorption depending on the polarization direction of an incident light. The facile methodology described in this study to generate oriented films of m-CNTs-in-RMS broadened the scope of potential applications of modulator devices and versatile functional composites with anisotropic physical properties.

Anisotropic Charge Carrier and Coherent Acoustic Phonon Dynamics of Black Phosphorus Studied by Transient Absorption Microscopy

Due to its corrugated hexagonal lattice structure, Black phosphorus (BP) has unique anisotropic physical properties, which provides an additional freedom for designing devices. Many body interactions, including interactions with phonon, is crucial for heat dissipation and charge carrier mobility in device. However, the rich properties of the coherent acoustic phonon, including anisotropy, propagation and generation were not fully interrogated. In this paper, the polarization-resolved transient absorption microscopy was conducted on BP flakes to study the dynamics of photoexcited charge carriers and coherent acoustic phonon. Polarization-resolved transient absorption images and traces were recorded and showed anisotropic and thickness-dependent charge carriers decay dynamics. The damping of the coherent acoustic phonon oscillation was found to be anisotropic, which was attributed to the polarization-dependent absorption length of the probe pulse. From the analysis of initial oscillation amplitude and phase of coherent acoustic phonon oscillation, we proposed that the direct deformation potential mechanism dominated the generation of coherent acoustic phonons in our experiment. Besides, we obtained the sound velocity of the coherent acoustic phonon from the oscillation frequency and the acoustic echo, respectively, which agreed well with each other. These findings provide significant insights into the rich acoustic phonon properties of BP, and promise important application for BP in polarization-sensitive optical and optoelectronic devices.

Three-Dimensional Optical Anisotropy of Low-Symmetry Layered GeS.

In-plane anisotropic two-dimensional (2D) materials, especially black phosphorus and ReS2, have attracted significant interest recently as they can provide one more dimension to manipulate their physical properties when compared with isotropic 2D materials. As a representative anisotropic 2D material, germanium monosulfide (GeS) has emerged as a new research hot topic in this field because of its unique in-plane anisotropic physical properties. Despite the rapid growing progress in the study of GeS, many of their fundamental optical anisotropies are still absent. Here, we report the three-dimensional (3D) optical anisotropy of GeS from theory to experiment. The 3D optical anisotropic properties including extinction, refraction, absorption, and reflection were systematically investigated through density functional calculations. The anisotropic refraction and reflection of GeS were experimentally verified by polarization-resolved optical microscopy and azimuth-dependent reflectance difference microscopy, respectively. Finally, a GeS-based linear dichroic photodetector was demonstrated with a dichroic ratio of 1.45 because of its polarization sensitive absorption. Our results provide deep insights into the optical anisotropy of GeS, which is important for the further development of GeS-based optoelectronic and optical devices.

Injection molding simulation of short fiber reinforced thermosets with anisotropic and non-Newtonian flow behavior

Discontinuous fiber reinforced polymers (FRPs) are one of the most complex materials used in volume production, composing a transient chemo-thermomechanical matrix behavior and fiber-induced anisotropic physical properties. The fibers induce anisotropic behavior not only in structural properties, but also during material flow and hence during mold filling, which in turn influences the final physical properties. Therefore, the fibers influence the material flow and vice versa, the material flow causes fiber-reorientation. This interaction is typically decoupled in state of the art process simulations. To consider the fiber-flow interactions, the present work provides a new simulation method for reactive injection molding, describing the fiber-induced anisotropic flow behavior by a fourth order viscosity tensor. The matrix viscosity is modelled non-Newtonian and curing kinetics are taken into account. Numerical examples demonstrate anisotropic effects to verify the model implementations. Furthermore, cavity pressure and fiber orientations are validated with experimental data, showing good agreement.

Strong anisotropy and its electric tuning for brownmilleriteSrCoO2.5films with different crystal orientations

Brownmillerite oxides ($A\mathrm{B}{\mathrm{O}}_{2.5}$) with long-range ordering of oxygen vacancies own a distinct superstructure formed by alternately stacked octahedral $\mathrm{B}{\mathrm{O}}_{6}$ and tetrahedral $\mathrm{B}{\mathrm{O}}_{4}$ planes. The one-dimensional oxygen vacancy channels within $\mathrm{B}{\mathrm{O}}_{4}$ layers usually lead to high ionic conductivity of brownmillerite oxides, demonstrating great application potential in solid-oxide fuel cells, the oxygen separation membrane, and catalyzers. Here, high quality brownmillerite-$\mathrm{SrCo}{\mathrm{O}}_{2.5}$ films have been epitaxially grown on differently oriented substrates by pulsed laser deposition. The anisotropic structural and physical properties of (110)- and (111)-oriented $\mathrm{SrCo}{\mathrm{O}}_{2.5}$ films were systematically investigated. We found, unlike the out-of-plane (001)-oriented $\mathrm{SrCo}{\mathrm{O}}_{2.5}$ films, the $\mathrm{Co}{\mathrm{O}}_{6}$ and $\mathrm{Co}{\mathrm{O}}_{4}$ planes would alternately stack along one of the [100] and [010] axes for (110)-oriented films and one of the [100], [010], and [001] axes for (111)-oriented films, forming coexisting crystal domains with different orientations. More importantly, the superstructure of these films could be reversibly tuned by alternately applying an electric field along two orthogonal directions, switching between an ordered and a disordered state. Corresponding to structural anisotropy, strong in-plane electronic anisotropy of the (110)-oriented $\mathrm{SrCo}{\mathrm{O}}_{2.5}$ film was revealed, which was also electrically tunable like the superstructure. This work demonstrates the approaches to modify the ionic conduction channels of brownmillerite oxides, opening avenues towards electrically tunable oxygen separation membrane and catalyzers.

Origin of anisotropy and compositional dependence of phonon and electron transport in ZnO based natural superlattices and role of atomic layer interfaces

Reaction of ZnO with trivalent ions can form natural superlattice (SL) compounds, which possess unusual structural characteristics and strong anisotropic physical transport properties. In this work, by synthesizing strongly textured bulk polycrystals of pure SL phases and performing characterization and measurements for both in-plane and cross-sectional directions, we revealed the strongly crystal orientation dependent transport properties. The observed compositional or SL interface spacing dependent electrical conductivity is largely attributed to the overall doping of ZnO wurtzite regions. The atomic layer SL interfaces are phonon barriers, and the interfacial thermal (Kapitza) resistance depends on SL interface spacing. The transport direction perpendicular to these SL interfaces are electron-conductive paths with remarkably higher electron mobility. There are electron potential barriers associated with these atomic layer SL interfaces. The effective and absolute potential barrier heights are determined, which are proportional to the natural conduction band discontinuities. The current study provides new findings and knowledge about the role of SL interfaces in phonon and electron transport process in these ZnO based natural SLs. The present work can be useful and inspiring to design and modify complex layer-structured compounds, including synthetic superlattice systems, for a variety of applications where energy carriers transport is involved.

Microstructures, Water Contents, and Seismic Properties of the Mantle Lithosphere Beneath the Northern Limit of the Hangay Dome, Mongolia

AbstractTo constrain the deformation, thermal evolution, and seismic properties of the mantle lithosphere beneath the Hangay Dome, we have analyzed the microstructures, crystal preferred orientations (CPO), and hydrogen concentrations of olivine and pyroxenes of 50 mantle xenoliths carried up by Cenozoic basalts from Zala, Haer, and Shavaryn‐Tsaram from Tariat, Mongolia. Most xenoliths are medium‐ to coarse‐grained spinel‐lherzolites, but four contain garnet + spinel. Coarse granular, highly annealed microstructures predominate. The microstructures are associated with well‐developed CPO, typical of deformation under high temperature, moderate pressure, and dry conditions. The hydrogen concentrations in olivine, orthopyroxene, and clinopyroxene are low and range around 5, 75, and 147 ppm H2O wt, respectively. Together, microstructures and CPO indicate that ductile deformation was followed by static recrystallization, which has annealed the microstructures but preserved the CPO and, hence, the anisotropy of physical properties. Lack of correlation between annealing and equilibrium temperatures suggest that the annealing is due to a long quiescence episode since the last deformation episode. Here, there is not evidence that the formation of Hangay Dome is associated with recent deformation in the lithospheric mantle. Calculated seismic properties show moderate seismic anisotropy, with fast propagation of P waves and polarization of S waves parallel to the flow direction and low birefringence for S waves propagating obliquely to the flow plane. The results are consistent with weak P wave anomalies but not with the strong low S wave velocity anomalies predicted by some tomographic models or with the high conductivity inferred from magnetotelluric data for the lithospheric mantle beneath the Hangay Dome.

Anisotropy of fracture toughness in nanostructured ceramics controlled by grain boundary design

The fracture toughness of nanostructured materials depends on anisotropic physical properties of individual microstructural features, their texture and/or topology. In this work, intentionally sculptured grain boundaries of low cohesive energy were used to form “weak” and “tough” crack propagation directions within a nanocrystalline TiN film, allowing to correlate the directional arrangement of grains and anisotropy of fracture toughness. By using a selective micromechanical testing approach, two different cracking directions were probed in a scanning electron microscope by loading microcantilever beam specimens prepared parallel and perpendicular to the stacked direction of the alternately tilted columnar grains. The fracture toughness along the sculptured grain boundaries was ~30% higher due to effective multiple crack deflection at the kink planes, which was not observed along weak cleavage planes in the stacked direction. The results indicate the fundamental importance of microstructural design in the synthesis of tough nanostructured ceramics, whose anisotropic mechanical properties can be controlled effectively by incorporating dedicated microstructural features of well-defined topology, orientation and density.

Anisotropic Physical Properties of Mafic and Ultramafic Rocks From an Oceanic Core Complex

AbstractWe analyzed the physical properties of altered mafic and ultramafic rocks drilled at the Atlantis Massif (Mid‐Atlantic Ridge, 30°N; Integrated Ocean Discovery Program Expeditions 304‐305 and 357). Our objective was to find a physical property that allows direct distinction between these lithologies using remote geophysical methods. Our data set includes the density, the porosity, P and S wave velocities, the electrical resistivity, and the permeability of mafic and ultramafic samples under shallow subsurface conditions (confining pressure up to 50 MPa equivalent to ~2‐km depth). In shallow subsurface conditions, mafic and ultramafic samples showed distinct differences in the density, the seismic wave velocities, and the electrical resistivity (mafic samples: 2,840 to 2,860 kg/m3, 5.92 to 6.70 km/s, and 60 to 221 Ω m; ultramafic samples: 2,370 to 2,790 kg/m3, 3.36 and 3.62 km/s, and 8 to 44 Ω m). However, we observed an overlap between physical properties of mafic and ultramafic rocks when we compared our measurements with those acquired from similar environments. The anisotropic homogeneous electrical resistivity inversion shows transverse isotropy symmetry, which is typical of a foliated microstructure. In both the inversion results and the thin sections, the direction of high resistivity axes of ultramafic rock samples is systematically perpendicular to the equivalent axes in mafic rock samples analyzed in this study. Our sample scale study suggests that electrical resistivity anisotropy may allow us to distinguish mafic and ultramafic lithologies via controlled source electromagnetic surveys. When surface conduction is negligible, the electrical resistivity can be used as proxy for permeability.

Magnetocrystalline anisotropy in the Kondo-lattice compound CeAgAs2

We report on the single crystal growth and anisotropic physical properties of CeAgAs$_2$. The compound crystallizes as on ordered variant of the HfCuSi$_2$-type crystal structure and adopts the orthorhombic space group $Pmca$~(\#57) with two symmetry inequivalent cerium atomic positions in the unit cell. The orthorhombic crystal structure of our single crystal was confirmed from the powder x-ray diffraction and from electron diffraction patterns obtained from the transmission electron microscope. The anisotropic physical properties have been investigated on a good quality single crystal by measuring the magnetic susceptibility, isothermal magnetization, electrical transport and heat capacity. The magnetic susceptibility and magnetization measurements revealed that this compound orders antiferromagnetically with two closely spaced magnetic transitions at $T_{\rm N1} = 6$~K and $T_{\rm N2} = 4.9$~K. Magnetization studies have revealed a large magnetocrystalline anisotropy due to the crystalline electric field (CEF) with an easy axis of magnetization along the [010] direction. The magnetic susceptibility measured along the [001] direction exhibited a broad hump in the temperature range 50 to 250~K, while typical Curie-Weiss behaviour was observed along the other two orthogonal directions. The electrical resistivity and the heat capacity measurements revealed that CeAgAs$_2$ is a Kondo lattice system with a magnetic ground state.

Anisotropy of mechanical and thermal properties of perovskite LaYbO3: first-principles calculations

ABSTRACTLaYbO3 ceramic material with a perovskite structure has the advantages of a high melting point, sintering resistance and high-temperature phase stability. It is a promising candidate for a structurally and functionally integrated material. However, the anisotropy of physical properties of LaYbO3 has rarely been studied. Herein, the anisotropy of the mechanical and thermal properties of LaYbO3 was studied by first-principles calculations. The elastic coefficients, Young’s modulus, Poisson’s ratio and minimum thermal conductivity of LaYbO3 were found to exhibit anisotropic characteristics. In particular, the sound velocity of the longitudinal wave was nearly twice that of the transverse wave. Especially, the minimum thermal conductivity of LaYbO3 at high temperature was found to be as low as 0.88 W/m K, indicating that the compound has potential for use in thermal insulation applications.

Ab initio and semiempirical modeling of excitons and trions in monolayer TiS3

We explore the electronic and the optical properties of monolayer ${\mathrm{TiS}}_{3}$, which shows in-plane anisotropy and is composed of a chain-like structure along one of the lattice directions. Together with its robust direct band gap, which changes very slightly with stacking order and with the thickness of the sample, the anisotropic physical properties of ${\mathrm{TiS}}_{3}$ make the material very attractive for various device applications. In this study, we present a detailed investigation on the effect of the crystal anisotropy on the excitons and the trions of the ${\mathrm{TiS}}_{3}$ monolayer. We use many-body perturbation theory to calculate the absorption spectrum of anisotropic ${\mathrm{TiS}}_{3}$ monolayer by solving the Bethe-Salpeter equation. In parallel, we implement and use a Wannier-Mott model for the excitons that takes into account the anisotropic effective masses and Coulomb screening, which are obtained from ab initio calculations. This model is then extended for the investigation of trion states of monolayer ${\mathrm{TiS}}_{3}$. Our calculations indicate that the absorption spectrum of monolayer ${\mathrm{TiS}}_{3}$ drastically depends on the polarization of the incoming light, which excites different excitons with distinct binding energies. In addition, the binding energies of positively and the negatively charged trions are observed to be distinct and they exhibit an anisotropic probability density distribution.

Ba1-xSrxTiO3 plates: Synthesis through topochemical conversion, piezoelectric and ferroelectric characteristics

ABO3-type perovskite crystallites with symmetrical crystal structures do not show a tendency to grow in the shape of rods and plates, which are of great scientific interest due to their anisotropic physical properties. A topochemical transformation is one of the most convenient approaches for the preparation of such defined-shape perovskite particles, the functional properties of which can be additionally tailored by the formation of solid solutions. In this study a one-step topochemical conversion reaction from a Bi4Ti3O12 template to A-site-substituted complex Ba1-xSrxTiO3 perovskite microplates was investigated in order to understand the mechanism and to determine the compositional, structural and morphological correlations between the template and the final plate-like particles. Based on our finding that Sr incorporates in a 2.7-times larger amount than expected from the initial Ba/Sr ratio (0 < x < 1, the plates with an arbitrary Ba1-xSrxTiO3 solid-solution composition could be prepared using this topochemical transformation. The tetragonal distortion of the Ba1-xSrxTiO3 plates, expressed as the c/a ratio, was found to decrease linearly from 1.0092 (x = 0) to 1.0037 (x = 0.23), while the compositions with higher x were cubic (c/a=1). According to a piezo-response force microscope (PFM) examination, Ba1-xSrxTiO3 plates with 0 ≤x ≤ 0.175 showed ferroelectric and piezoelectric characteristics. The temperature of the ferroelectric-to-paraelectric phase transition, as determined by differential scanning calorimetry (DSC), linearly decreased from 124 °C (x = 0) to 88 °C (x = 0.11). XRD examinations revealed a strong (001) preferential orientation for the plates (0 ≤ x ≤ 0.11) and the typical (001)/(100) peak splitting indicated the presence of c- and a-domains. The successful preparation and design of Ba1-xSrxTiO3 plates increase the potential of this topochemical transformation for the preparation of plates with a variety of solid-solution compositions and controlled characteristics.

Single crystal growth and anisotropic physical properties of Sm4Co3Ga16

We have synthesized high quality single crystals of Sm4Co3Ga16 with gallium flux and investigated its physical properties with electrical resistivity, magnetization and specific-heat measurements. Antiferromagnetic transition below 6.7 K has been detected. No superconducting transitions have been dectected down to 0.5 K from our single crystals. Based on our experimental result, Sm3+ state in Sm4Co3Ga16 is likely well localized, in which stable magnetic moment in its doubly degenerated ground state contributes to the magnetic order with little interference of Kondo type of interaction.

Thermal cloak with adaptive heat source to proactively manipulate temperature field in heat conduction process

Thermal cloaks can thermally hide an object without disturbing background thermal field. The coordinate transformation method for designing conventional thermal cloaks face some challenges that the physical properties of metamaterials are required to be anisotropic and inhomogeneous. Furthermore, the coordinate transformation is not applicable for complex geometrical conditions. In this study, a proactive thermal cloak is proposed. The cloak contains two concentric annular zones: one with high thermal conductivity and another with adaptive heat source. The cloaked zone is surrounded by the high thermal conductivity zone. The high thermal conductivity zone keeps the object in the cloaked zone from thermally being affected by outside zones. The heat source zone adjusts the background thermal field without any distortion. The thermal cloak with an analytical heat source distribution is presented for the 2D and 3D background thermal fields with uniform gradient. The adaptive heat source in the thermal cloak is designed by inverse problem theory of a numerical method for the 2D arbitrary background thermal field. This proactive thermal cloak can avoid the issue of anisotropic physical properties for the conventional thermal cloak designed with coordinate transformation method. The heat source thermal cloak with relatively easy implementation can manipulate temperature field proactively without contact. This thermal cloak is applicable for arbitrary background thermal fields and complex geometrical conditions by a numerical design approach. The proposed thermal cloak opens a new strategy to manipulate the thermal field with adaptive heat source.

3D crystallographic alignment of alumina ceramics by application of low magnetic fields

Non-cubic crystals exhibit anisotropic physical and functional properties. Microscopic crystallites as constituents of polycrystalline materials are randomly oriented, thus polycrystalline ceramics lack the anisotropic properties of their monocrystalline counterparts. We propose a technology that exploits the synergy between magnetic alignment and colloidal ceramics processing, and enables to independently tune the orientation of grains in different sample regions by infinitesimal magnetic fields (<10 mT). The grain pivot mechanism enables the emulation of single crystals, as well as the creation of large complex-shaped ceramic elements with designed crystallographic landscapes and spatially and directionally tuned properties. Ultra-high magnetic response arises from magnetic shape anisotropy of platelet-shaped seed crystallites coated with small amounts of iron oxide nanoparticles. To control crystallographic growth directions during subsequent annealing procedures, the seeds are dispersed and aligned in a matrix of chemically identical, but much finer spherical particles. This technology opens an avenue to remarkably improve structural and functional properties of ceramic elements employed in numerous industrial applications.

On the structural anisotropy of physical and mechanical properties of a Bunter Sandstone

Studies of structural anisotropy of rocks contribute to the understanding of their mechanical behaviour variation in a broad spectrum of geological settings. In this work we characterise the lithological variation and the mechanical behaviour of the Trendelburg beds, a fine-grained subarkose from the Bunter Sandstone, with moderate effective porosity (10%) and low permeability (0.5 mD). Traditional triaxial compression tests were carried out with varying confining- and pore pressures in water saturated specimens (7 cm diameter ×14 cm length). Ultrasonic velocity, permeability, deformability, compressive strength, mechanical work and fracture pattern were determined in two directions of anisotropy (0° and 90°) with respect to bedding. Changing the angle of anisotropy leads to different reactions to the influence of lithological heterogeneities, which reaches a maximum when arranged parallel to σ1. The Trendelburg beds has significant anisotropy effects, which tend to increase with effective pressure. The effects of a structural anisotropy due to bedding are associated with an anisotropy of physical properties, stress state, pore pressure and likely pore space distribution. Mechanical properties are direction dependent, however, the influence of lithological factors may diverge between both directions of anisotropy as pressure increases.

Physical property anisotropy of foliated fault rocks: Study from the Nobeoka Thrust, Shimanto Belt, southwest Japan

AbstractTo investigate the physical property anisotropies of foliated fault rocks in subduction zones, the hanging wall phyllites and footwall cataclasites exhumed along the Nobeoka Thrust, a fossilized out‐of‐sequence‐thrust in the Shimanto Belt, Japan, was focused. Discrete physical property (electric resistivity, P‐ and S‐wave velocities, and porosity) measurements were conducted employing geologic coordinates (depth‐parallel direction, strike direction, and maximum dip direction of foliation), using the core samples obtained from the Nobeoka Thrust Drilling Project and compared the data to borehole geophysical logs. A higher sample P‐wave velocity (Vp), lower S‐wave velocity (Vs), higher Vp/Vs, and lower sample porosity and resistivity compared to the logs, are inferred to have been caused by the larger sampling scale of the logs and lower fluid saturation of the borehole. The phyllites and cataclasites exhibited substantial vertical and horizontal anisotropy of Vp (0.4–17.3 % and 2.7–13.8 %, respectively), Vs (0.5–56 % and 7.7–43 %, respectively), and resistivity (0.9–119 % and 2.0–65.9 %, respectively). The physical property anisotropies are primarily affected by the dip angles of foliation. The fault rocks that have gentler dip angles exhibit a higher Vp in the strike and maximum dip direction and a lower Vp in the depth‐parallel direction. In contrast, the fault rocks that have steeply dipping structures show a higher Vp in the strike and depth‐parallel directions with a lower velocity in the maximum dip direction. Resistivity anisotropy show a trend opposite to that of the Vp in relation to the dip angles. Our results show lower Vp anisotropy than those obtained in previous studies, which measured wave speeds perpendicular or parallel to foliation under confining pressure. This study highlights the significance of dip angles on vertical properties in geophysical surveys across foliated fault rocks.

15N\u201313C Dipole Couplings in Smectic Mesophase of a Thermotropic Ionic Liquid

Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole–dipole spin couplings. While 13C–1H and 15N–1H dipolar NMR spectra can be routinely acquired in samples with natural isotopic abundance, recording 15N–13C dipolar NMR spectra is challenging because of the unfavourable combination of two rare isotopes. In the present study, an approach to measure 15N–13C dipole-dipole NMR spectra in static liquid crystalline samples with natural abundance is introduced. We demonstrate that well-resolved spectra can be recorded within 10 h of experimental time using a conventional NMR probe and a moderately strong magnetic field. The technique is applied to a thermotropic smectic mesophase formed by an ionic liquid with imidazolium-based organic cation.