High-resolution X-ray Diffraction Research Articles

Effect of Mo on the coherent interface features of γ′-phase strengthened Co-based superalloys

Molybdenum (Mo) addition was investigated for its influence on the interfacial characteristics of γ′-phase strengthened Co-based superalloys with γ/γ′ dual phases. Advanced characterization techniques, including scanning transmission electron microscopy (STEM), atom probe tomography (APT), and high-resolution X-ray diffraction (HR-XRD), were employed for this purpose. Mo addition was found to increase the compositional and structural widths of the γ/γ′ interface. This was accompanied by segregation of Mo and Co at the interface, attributed to the reduction of interfacial energy. Additionally, Mo addition led to a decrease in the lattice misfit between the γ-matrix and γ′-phases. Those results enhanced interface stability, contributing to improved high-temperature stability. This study offers valuable insights into the mechanisms of alloying and the microstructural stability of Co-based superalloys.

Holmium-doped TbVO4 as a highly potential magneto-optical crystal for Faraday isolator

Tb1-xHoxVO4 (THV) magneto-optical crystal with diameter of 27 mm and length of 40 mm was grown by the Czochralski (Cz) technique for the first time. The structural perfection of THV crystal was studied by the high-resolution X-ray diffraction rocking curve measurement, proving the high crystallinity quality of THV. THV shows high transmittance of greater than 75 % within the wavelength range of 665–1600 nm. The Verdet constants of THV at 532, 633 and 1064 nm are 370, 226 and 56 rad·m−1T−1, 40 %–95 % higher than these of commercial TGG crystal. Additionally, THV exhibits lower absorption coefficient (0.05 cm−1), higher magneto-optical figure of merit (175 deg/dB) and extinction ratio (43 dB) at 1064 nm compared with TGG. Evaluation of thermal performance and laser-induced damage threshold of THV were also made to promote the potential application in high-power optical isolators.

Optical, Structural, and Synchrotron X-ray Absorption Studies for GaN Thin Films Grown on Si by Molecular Beam Epitaxy.

GaN on Si plays an important role in the integration and promotion of GaN-based wide-gap materials with Si-based integrated circuits (IC) technology. A series of GaN film materials were grown on Si (111) substrate using a unique plasma assistant molecular beam epitaxy (PA-MBE) technology and investigated using multiple characterization techniques of Nomarski microscopy (NM), high-resolution X-ray diffraction (HR-XRD), variable angular spectroscopic ellipsometry (VASE), Raman scattering, photoluminescence (PL), and synchrotron radiation (SR) near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. NM confirmed crack-free wurtzite (w-) GaN thin films in a large range of 180-1500 nm. XRD identified the w- single crystalline structure for these GaN films with the orientation along the c-axis in the normal growth direction. An optimized 700 °C growth temperature, plus other corresponding parameters, was obtained for the PA-MBE growth of GaN on Si, exhibiting strong PL emission, narrow/strong Raman phonon modes, XRD w-GaN peaks, and high crystalline perfection. VASE studies identified this set of MBE-grown GaN/Si as having very low Urbach energy of about 18 meV. UV (325 nm)-excited Raman spectra of GaN/Si samples exhibited the GaN E2(low) and E2(high) phonon modes clearly without Raman features from the Si substrate, overcoming the difficulties from visible (532 nm) Raman measurements with strong Si Raman features overwhelming the GaN signals. The combined UV excitation Raman-PL spectra revealed multiple LO phonons spread over the GaN fundamental band edge emission PL band due to the outgoing resonance effect. Calculation of the UV Raman spectra determined the carrier concentrations with excellent values. Angular-dependent NEXAFS on Ga K-edge revealed the significant anisotropy of the conduction band of w-GaN and identified the NEXAFS resonances corresponding to different final states in the hexagonal GaN films on Si. Comparative GaN material properties are investigated in depth.

Growth of AlGaN alloys with ∼ 90 % AlN mole fraction by plasma-assisted molecular beam epitaxy: Indication of phase-segregation effects

AlGaN alloys with very high AlN mole fraction (∼90 %) were grown by plasma-assisted molecular beam epitaxy (PA-MBE) and their alloy properties were investigated by high-resolution X-ray diffraction (HR-XRD) measurements. Growth was carried out employing a series of group III/V ratios and for samples grown under a high group-III regime, phase-segregation in the alloy was evident from a characteristic splitting of the AlGaN (0002) peak in the HR-XRD pattern. With decreasing excess group-III conditions the separation of peak positions continuously reduced, till a single peak was observed. However, for samples where such splitting was absent, spontaneous superlattice peaks were seen at lower incident angles of the XRD patterns indicating the presence of long-range atomic ordering (LRAO). Thus, for AlGaN alloys with extremely high Al content, effects of phase-segregation, or of LRAO were observed, depending on the kinetics of growth. These results on phase-segregation effects are expected to promote the development of high-efficiency deep ultraviolet emitters for skin-safe germicidal action by mitigating the detrimental effect of dislocations and related non-radiative recombination centers through carrier localization processes at potential minima.

Dissecting of Atomic Morphology of Superfine Pulverized Coal Based on X-ray Pair Distribution Function

Resolving the atomic structure information of the aromatic layers in coal plays a crucial role in understanding the generation mechanisms of NOx during coal combustion and further reducing the formation of NOx from the source. This study reveals the distribution of X-ray diffraction bands of superfine pulverized coal using a high-resolution synchrotron radiation X-ray Diffraction (HRXRD) facility, discussing the distribution of atomic distances and atomic density in aromatic layers through pair distribution function (PDF) methods. Furthermore, the influences of mechanochemistry on the evolution of atomic morphology are focused on. The results show that the PDF of coal gradually stabilizes when r > 8 Å, showing the short-range order of graphite-like structure. Additionally, due to the limitations of scanning angle and X-ray energy, atomic distances in aromatic layers for coal are significantly greater than that of pure graphene. Enhanced mechanochemical effects make the peaks 1, 2, and 3 of coal PDF more similar to graphene's by condensing alkyl side chains into smaller, regular aromatic layers when the particle size decreases. With the enhancement of mechanochemical effects, coals with different metamorphic degrees exhibit different aromatic evolution patterns. The aromaticity of NMG coal first decreases and then increases, while the aromaticity of YQ coal shows the opposite trend. The results can provide deeper insights into the atomic structure of coal macromolecular, which can facilitate the advancement of novel ultra-low NOx combustion methods and support the construction of precise coal macromolecular models.

Radiation-Induced Synthesis and Superparamagnetic Properties of Ferrite Fe3O4 Nanoparticles.

Ultra-small magnetic Fe3O4 nanoparticles are successfully synthesized in basic solutions by using the radiolytic method of the partial reduction in FeIII in the presence of poly-acrylate (PA), or by using the coprecipitation method of FeIII and FeII salts in the presence of PA. The optical, structural, and magnetic properties of the nanoparticles were examined using UV-Vis absorption spectroscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and SQUID magnetization measurements. The HRTEM and XRD analysis confirmed the formation of ultra-small magnetite nanoparticles in a spinel structure, with a smaller size for radiation-induced particles coated by PA (5.2 nm) than for coprecipitated PA-coated nanoparticles (11 nm). From magnetization measurements, it is shown that the nanoparticles are superparamagnetic at room temperature. The magnetization saturation value Ms = 50.1 A m2 kg-1 of radiation-induced nanoparticles at 60 kGy is higher than Ms = 18.2 A m2 kg-1 for coprecipitated nanoparticles. Both values are compared with nanoparticles coated with other stabilizers in the literature.

Optical constants and thickness determination of La[formula omitted]Sr[formula omitted]MnO3 thin films on Nb:SrTiO3 substrates by spectro-ellipsometry: Combination of optical and X-ray techniques

40 nm thick La2/3Sr1/3MnO3 (LSMO) thin films were epitaxially grown by Pulsed Laser Deposition (PLD) onto niobium doped SrTiO3 (Nb:STO) substrates, with different Nb concentration from 0.01%wt to 0.5%wt. The optical characterization of the heterostructures by spectroscopic ellipsometry enables us to extract the optical constants of the manganite heteroepitaxial layer at room temperature. Performing spectrophotometry in the same wavelength range brings a useful cross-validation of the extracted results. In addition, the thickness evaluation of the LSMO layer by spectro-ellipsometry is further validated by both High Resolution X-ray diffraction and X-ray reflectivity, as well as a Transmission Electron Microscopy cross section, taken as a physical reference. This study validates quantitatively the spectro-ellipsometry as a suitable routine tool to measure accurately both thickness and complex refractive index of the LSMO thin film, picturing their peculiar electrical behaviour between both metallic and insulating phases. The relative error on the thickness measurement between X-ray and ellipsometry is less than 5%. The LSMO complex refractive index enabled also a simultaneous estimation of further material properties, such as the optical gap ωg or the mass density ρm, determined with less than 1.5% relative error compared to X-ray reflectivity results.

Structural and optical characterizations of cubic GaN layers grown by MOVPE on GaAs(114) substrate

GaN-based structures have been employed in a range of electronic and optoelectronic applications. Despite the extensive utilization of hexagonal GaN (h-GaN), certain devices, such as green-emitting lasers, face limitations. Conversely, cubic GaN (c-GaN) proves advantageous in addressing challenges associated with h-GaN, thanks to its reduced bandgap and being free of the strong polarization fields resulting in enhanced radiative recombination rate. Yet, c-GaN possesses a metastable phase during growth, which can negatively impact the structure of the films. Optimizing the growth conditions can significantly improve material quality and, hence, device performance. In our present work, we report the growth of cubic GaN on GaAs (114) substrates using metal-organic vapor phase epitaxy (MOVPE) with various thicknesses. Morphological analyses demonstrated a grain structure with increased surface roughness versus layer thickness. Such measurements enabled us to study the texture and growth mode evolutions. High-resolution X-ray diffraction 2 θ-ω scans showed a (002) c-GaN preferred orientation with hexagonal inclusions. The optical characteristics of the investigated layers were explored using cathodoluminescence measurements, revealing a correlation between the stress state and layer thickness.

Numerical and experimental study on effect of induction heating parameters on the coating of Zn layer on mild steel

The objective of the study is to determine the most effective induction heating parameters for melting pure zinc selectively over the mild steel substrate surface. The numerical simulation on effect of induction heating parameters on the mild steel substrate is studied using COMSOL Multiphysics 5.6 software. The optimised effective parameters are used for the experimental analysis for the validation. Variables such as coil configuration, stand-off distance (SOD), coil current and frequency were systematically changed, and optimal settings were chosen on the basis of time temperature contour curve and the heating rate within the material. Results of the numerical analysis portrayed that a pancake coil geometrical configuration, SOD of 2 mm, coil current of 300 A and alternating frequency of 300 kHz were found as the optimum set of parameters for the effective surface repair. An experimental investigation was carried out by depositing a thin layer of zinc on mild steel substrate using the optimized parameters. The surface integrity of the coated specimen was examined through the high-resolution optical microscopy, X-ray diffraction and electron back scattered diffraction (EBSD) techniques. The hardness property of the coated specimen was examined with a Vickers microhardness tester. The microstructure analysis and hardness measurement showed that consistent coating is achieved without affecting the base metal/substrate properties. The experimental results very much coincide with the numerical simulation.

Synthesis and Physical Properties of the Misfit Layered Compound (EuS)1.13(NbSe2)2.

A new misfit layered compound with the stoichiometry (EuS)1+δ(NbSe2)2 (δ ≈ 0.13) has been successfully synthesized. High-resolution transmission electron microscopy and powder X-ray diffraction confirm the misfit structure with (EuS)-(EuS) spacing of 18.30(1) Å. Magnetization, electrical resistivity, heat capacity, and thermal transport measurements show that the material is a heavily doped semiconductor or poor metal with a low thermal conductivity of ∼1 W/m K and an antiferromagnetic ordering transition at TN = 4.7 K. In contrast to the parent materials, the misfit is neither ferromagnetic nor superconducting down to T = 0.4 K. We find evidence of a field-driven transition to a ferromagnetic state due to reorientation of ferromagnetic EuS layers at μoH = 0.5 T at T = 2 K.

A process-based geochemical framework for carbonate sediments during marine diagenesis

A significant proportion of marine calcium carbonate sediments are comprised of metastable minerals that are susceptible to diagenetic alterations during burial. These reactions can reset the geochemical signature of sediments and pore fluids and influence elemental cycling in the ocean. However, the timing and mechanisms by which these reactions take place are poorly constrained. This study uses cores drilled on the slope of the Great Bahama Bank to provide quantitative constraints on important diagenetic reactions; namely respiration-driven dissolution, authigenic carbonate mineral formation, and conversion of aragonite to low Mg calcite (LMC). We perform detailed mineralogical characterization using newly acquired, high resolution X-ray diffraction (XRD) data and over 1000 reanalyzed XRD scans, characterize sediments texturally and elementally using electron microprobe data, calculate pore fluid saturation state with respect to aragonite using a Pitzer ion interaction approach, and use pore fluid chemistry and experimental distribution coefficients to predict authigenic carbonate compositions. These data suggest that aerobic organic matter oxidation, enabled by the advection of oxygenated seawater throughout the upper ∼ 30 m interval of sediment, causes undersaturation and thus dissolution of biogenic high Mg calcite (HMC) and aragonite. Deeper, anaerobic organic matter oxidation takes over and causes supersaturation, promoting authigenic precipitation in the form of HMC, which in turn decreases pore fluid Mg/Ca and promotes aragonite conversion to LMC. One novel aspect of this study is the identification of three types of calcites using the newly acquired XRD and electron microprobe data. Based on their unique crystallographic characteristics and chemical compositions, these types of calcites are interpreted to represent pelagic biogenic LMC, bank-derived biogenic HMC, and authigenic HMC precipitated from pore fluids. Notably, the composition of the authigenic calcite matches that predicted to precipitate from pore fluids using an empirical Mg partition coefficient in calcite. Calcites that form authigenically and from aragonite via replacement are suggested to recrystallize with burial as evidenced by the decrease in Mg content and micro-strain. This process-based geochemical framework assigns diagenetic processes to a specific depth window within the sediment column and paves the way for a mechanistic understanding of carbonate diagenesis, one that is rooted in thermodynamic and kinetic bases.

Similarities and differences in the ordering at short and long ranges in a NaNbO3 based Pb-free smart system: a key to functional properties

In this study, we have investigated the crystal structure of the solid solution of antiferroelectric NaNbO3(NN) with ferroelectric Ba0.9Ca0.1TiO3(BCT), i.e. (1−x)NN- xBCT for 0⩽x⩽1.0 using High-resolution powder x-ray diffraction (HR-XRD) data, dielectric measurements in conjunction with Raman spectroscopic studies. The investigation of long-range structural phase transitions as a function of composition(x) using x-ray diffraction is complemented by short-range structural insights from Raman spectroscopy. The incorporation of BCT disrupts the delicate antiferroelectric ordering of NN and stabilizes various ferroelectric phases with increasing BCT content(x). At x = 0.10, the simultaneous presence of two ferroelectric phases viz., Pmc21 and Amm2, results in a threefold rise in remanent polarization compared to off-boundary compositions. The composition with higher BCT content (i.e. x⩾0.50 ) has shown the anomalous existence of two long-range cubic structures, both of which are characterized by Pm 3¯ m space group. In spite of having a two-phase long-range centrosymmetric structure, we have observed a slim Polarization vs. Electric field(P-E) hysteresis loop for 0.50⩽x⩽0.80 . This contrapositive behavior (i.e. hysteresis loop in a centrosymmetric structure) has been attributed to the correlations among local static polar distortions of rhombohedral type ascertained using Raman spectroscopy. The coexistence of two ferroelectric phases at room temperature(for x = 0.10) and a slim hysteresis loop (for 0.50⩽x⩽0.80 ) make these compositions potential ingredients for applications in ferroelectric memory and energy storage devices.

Ferroelectric behavior arising from polar topologies in epitaxially strained SrTiO3-δ ultrathin films

In this work, we show that epitaxially strained SrTiO3-δ thin films, grown by ion-beam sputtering onto (001)Nb:SrTiO3 substrates, exhibit a ferroelectric behavior. At the atomic-scale, through high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images, it was possible to identify the presence of polar nanoregions with non-trivial polar topological structures in the SrTiO3-δ film, which are induced through oxygen vacancies. To further confirm the presence of strained regions with a polar structure, Raman spectroscopy and high-resolution X-ray diffraction were employed and it was possible to confirm the presence of a tetragonal structure in the SrTiO3-δ film, with a tetragonality ratio (c/a) of 1.005. Scanning probe microscopy and macroscopic polarization-electric field hysteresis loops show ferroelectric behavior with maximum polarization of ∼1.5 μC/cm2, remnant polarization of ∼0.4 μC/cm2 and coercive field of ∼0.3 MV/cm. This work opens a window for exploring novel polar topological effects in sub-10 nm thin film materials for non-volatile memory application.

Synthesis and characterization of C@CdS core-shell structures for high-performance capacitors

The present study investigates the synthesis and characterization of carbon@cadium sulphide (C@CdS) core-shell nanostructures for their potential application in electrochemical double-layer (ECDL) capacitors. Two distinct synthesis methods, hydrothermal route and co-precipitation method, were employed to fabricate C@CdS materials, each resulting in unique morphology and growth mechanisms. Detailed microstructural analyses, including high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD), revealed nanosheets in co-precipitated sample (CCSP) and core-shell structures in hydrothermally synthesized sample (CCSA). Optical investigations using UV-Vis spectroscopy provided insights into the absorbance properties of the synthesized materials. Electrical characterization, including frequency response testing and impedance analysis, demonstrated distinct capacitive behaviours for CCSP and CCSA, highlighting their potential for use in energy storage applications. Electrical characterization, including frequency response testing, impedance analysis, and galvanostatic charge-discharge (GCD) curve analysis, demonstrated distinct capacitive behaviours for CCSP and CCSA, highlighting their potential for use in energy storage applications. The integration of optical, structural, and electrical analyses provides a comprehensive understanding of the synthesized C@CdS core-shell nanostructures, offering insights into their potential application for ECDL capacitor technology and other emerging energy storage applications. Further optimization of synthesis parameters and exploration of scalable production methods are suggested for future research endeavors.

Competitive nature of weak anti-localization and weak localization effect in Cr-doped sputtered topological insulator Bi2Se3 thin film

In the present study, we have investigated the effect of magnetic Cr doping on the transport properties of a sputtered Bi2Se3 thin film on the SrTiO3 (110) substrate. The high-resolution x-ray diffraction and Raman spectroscopy measurements revealed the growth of rhombohedral Bi2Se3 thin films. Further electronic and compositional analysis was done by x-ray photoemission spectroscopy and Rutherford backscattering spectroscopy, and the x-value was estimated to be 0.18 in the Bi2−xCrxSe3 thin film. The variation in the resistivity with temperature (2–300 K) revealed the metallic nature in undoped Bi2Se3 up to 30 K and upturn resistivity below 30 K. The Cr-doped Bi2Se3 resistivity data show a traditional semiconducting nature up to 25 K and take an abrupt upturn resistivity below 25 K. The resistivity behavior of both samples was explained by adopting a model that consists of the total resistance, a combination of bulk and surface resistance in parallel. The bulk bandgap value determined by this method is obtained to be 256 meV in an undoped Bi2Se3 thin film. Magnetoconductance data of the undoped thin film revealed a weak anti-localization (WAL) effect, while the Cr-doped thin film showed a weak localization (WL) effect at low temperatures (<50 K). At low magnetic field and low temperature, a competing nature of WAL and WL effects was prominent in the Cr-doped film. A drastic increase in the electrical resistance suggests that Cr doping can significantly modify the electrical properties of Bi2Se3 thin films, which could have potential applications in futuristic devices.

Deposition time dependent structural and optical properties of polycrystalline [formula omitted] films

Sputtering-derived InGaZnO4 (IGZO) thin films were grown on quartz substrates and undergone post-deposition annealing at 700 °C for 2hr in N2 ambient. The influence of deposition time or film thickness on the morphological, structural and optical properties of polycrystalline IGZO thin films has been systematically investigated by means of characterization from field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectrophotometer. Results of AFM have shown that the root-mean-square (RMS) surface roughness of the IGZO films increases from 0.888 to 2.640 nm as the deposition time is extended from 50 to 250min. Analysis of XRD indicates that all the films are in polycrystalline phase, with crystallites growing into larger size accordingly to increasing deposition time. Appealingly and scarcely ever reported, the XRD diffraction planes can be separated into three domains, such as (0 0 l), (1 0 l) and (1 1 l) with different growth thicknesses. Optical measurement suggests that the optical bandgap have redshifted from 3.55 to 3.31eV at longer deposition time. Related mechanics about the change in physical properties against deposition time have been elaborated in detail. The validity of Swanepoel method, 1983 in deriving the refractive index of thick IGZO films has also been discussed.

Abrupt ternary III–V metamorphic buffers

Emerging quantum materials as well as novel traditional electronic and photonic materials may enable a new generation of information science devices if they can be synthesized on suitable substrates. Additionally, material and device designs may benefit from tunable properties through engineered epitaxial strain for the manipulation of the electronic character. In this work, three series of III–V ternary alloys, GaInSb, AlInSb, and InAsSb, are grown via molecular beam epitaxy on GaAs (001) substrates to explore the flexibility of abrupt metamorphic epitaxial layers with tunable lattice parameters between 6.135 and 6.479 Å. Their deposition on both homomorphic GaAs and pseudomorphic AlAs buffers is also explored. The structures of these alloys are characterized via reflection high-energy electron diffraction, high-resolution x-ray diffraction, atomic force microscopy, and transmission electron microscopy to assess their suitability as stable buffer layers with wide variability of accessible lattice parameters.

Molecular beam epitaxy growth and characterization of GePb alloys

Pb based group-IV alloys such as GePb have been gaining interest as a potential alternative for infrared detectors, quantum materials, and high-speed electronic devices. Challenges remain in their growth due to the extremely low solid solubility of Pb in the Ge–Pb system. This paper reports molecular beam epitaxy growth of GePb alloy thin films on Ge(100) substrates. Effusion cells of Ge and Pb are used to control the flux ratio independently. The optimal substrate temperature is found to be near the thermocouple temperature of 300 °C based on the characterization of the grown films using high-resolution x-ray diffraction. A large change in the Ge:Pb beam equivalent pressure ratio from 10:1 to 1:1 results in only a minimal increase of the Pb composition from 0.74% to 2.84% as estimated from Raman spectroscopy and Rutherford backscattering spectrometry. Scanning electron microscopy images show a large volume of Pb islands on the surface that form into either long trapezoidal rods or uniform droplets, with increasing Pb flux and growth time the density of Pb islands increased.

A new sesquiterpene from Syringa oblata

In this study, the chemical components of ethanol extract from the aromatic parts of Syringa oblata were systematically separated and purified by silica gel column chromatography, thin layer plate preparation and liquid phase preparation. Combined with ultraviolet analyzer(UV), infrared analyzer(IR), nuclear magnetic resonance analyzer(NMR), high resolution mass spectrometer(HR-ESI-MS), X-ray diffraction and other spectrum technology as well as literature physicochemical data comparison methods for structural identification, a total of 10 compounds were identified. They were identified as oblatanoid D(1),(-)-T-muurolol(2), oblatanoid E-G(3-5), 14-noreudesma-3-hydroxy-3-en-2,9-dione(6), 1-isopropyl-2,7-dimethylnaphthalene(7), isocoradiol(8), α-calacorene(9), cadin-4-en-1-β-ol(10). Compound 1 is a new sesquiterpene compound that has not been reported, and the other 9 compounds are isolated from S. oblata for the first time. The compound 1 has a significant protective effect on the LPS-induced inflammatory injury model of RAW264.7 cells.

Pressure/temperature-assisted crystallographic engineering–A strategy for developing the infrared phosphors

Light-emitting diodes utilizing the near-infrared (NIR), harnessed through the doping of Cr ion with structural engineering to tune the luminescent properties, provide a compelling avenue for cutting-edge high-tech industries. Overcoming the challenge of altering the local coordination surrounding the activators is crucial for advancing novel NIR phosphors. Here, we propose a pressure-assisted crystallographic engineering strategy to design the new Cr-doped phosphors. Implementing this approach at high temperature and pressure facilitates the phase transition from β-LiGaO2:Cr to α-LiGaO2:Cr, enabling the LiGaO2:Cr material to emit the NIR light, which was initially unattainable. Additionally, we demonstrate the in-situ monitoring of the reverse phase transition from α-LiGaO2:Cr to β-LiGaO2:Cr, validated by in-situ temperature-dependent high-resolution synchrotron X-ray diffraction. Furthermore, α-LiGaO2:Cr and β-LiGaO2:Cr exhibit unexpected optical properties characterized through synchrotron X-ray absorption, photoluminescence, temperature-dependent, and pressure-dependent analyses. Moreover, the α-LiGaO2:Cr shows strong mechanoluminescence and persistent luminescence. This research paves the way for developing novel NIR phosphors and sheds light on the analyses of pressure-assisted research.