The ambient- and high-pressure behavior of the ferrimagnet Ni4Nb2O9 (orthorhombically distorted honeycomb structure), is investigated using NMR, Raman spectroscopy, and synchrotron XRD. Ambient-pressure NMR measurements reveal, despite its orthorhombic symmetry, the local environment of Ni4Nb2O9 closely resembles that of its trigonal analogue Mn4Nb2O9. In contrast, substantially different paramagnetic shifts observed in the two compounds reflect their distinct average crystal symmetries, governing orbital overlap and magnetic exchange pathways. Under external pressure, Ni4Nb2O9 exhibits pronounced sensitivity to lattice distortions and phonon instabilities. Three isostructural transitions are identified near 2, 6, and 10 GPa, manifested by mode splitting, frequency shifts, line broadenings, intensity anomalies, and slope changes in the evolution of lattice parameters. At higher pressure, around 13 GPa, signatures of an incipient long-range structural transition from orthorhombic Pbcn to monoclinic P2/c symmetry emerge, signaling the onset of a symmetry-lowering transformation. The anomalous softening of the 192 cm^-1 Raman mode, accompanied by multiple linewidth and spectral-weight anomalies, serve as a key fingerprint of these structural instabilities, linking local symmetry breaking at low pressures to the long-range transition into the P2/c phase. Notably, pronounced linewidth anomalies, strongly anisotropic pressure coefficients, together with a marked enhancement of the intensity of the low-frequency branch over the 2-13 GPa range, point toward a pressure-induced regime influenced by coupled spin, orbital, and lattice degrees of freedom. The close correspondence of transition pressures in Ni4Nb2O9 and those reported for Mn4Nb2O9 highlights a common mechanism rooted in their similar local structural environments, as revealed by NMR.

The high-pressure behavior of two Mn-based honeycomb-structured magnetoelectric materials, Mn4Nb2O9 (MNO) and Mn4Ta2O9 (MTO), was investigated using Raman spectroscopy, synchrotron x-ray diffraction, and density functional theory (DFT) calculations. In MTO, the application of a small pressure of only 0.5 GPa induces an isostructural transition driven by local symmetry breaking. With further increase in pressure, three additional isostructural transitions are observed at about 3.2, 6, and 10 GPa, followed by the onset of a long-range structural transition near 14 GPa, where the ambient P-3c1 phase begins to transform into a P2/c phase. These two phases coexist up to 27 GPa. The Nb analogue, MNO, also exhibits similar isostructural transitions at about 2, 6.6, and 10 GPa. However, the onset of the mixed P2/c and P-3c1 phases occurs at a slightly lower pressure of 12.5 GPa, with phase coexistence extending up to 26.5 GPa. These long-range transitions are supported by pressure-dependent enthalpy changes obtained from DFT calculations. Rietveld refinement reveals pronounced anisotropic lattice compression, with a 42 to 49 percent difference between the c and a axes, leading to a notable reduction in the c/a ratio. This anisotropy may strengthen interlayer coupling and promote magnetic ordering under compression, consistent with the appearance of Raman modes similar to those reported at low temperatures, together with anomalous changes in Raman mode linewidth and intensity. The marked changes in Raman self-energy parameters, anomalies in the reduced pressure-Eulerian strain profile, and the onset of local symmetry breaking at much lower pressures in MTO than in MNO highlight the important role of differences in spin-orbit coupling strength and orbital hybridization associated with Nb5+ and Ta5+ cations.

Compositional tuning of CdTe-based II-VI semiconductors plays an important role in optimizing physical properties required for detector grade, magneto-optical and optoelectronic materials. In this work, undoped Cd0.90Mn0.10Te1-ySey (y = 0, 0.02, 0.04, 0.06) single crystals were grown by the vertical Bridgman technique to explore the influence of selenium incorporation on their structural, optical, electrical, and magnetic behavior. All compositions confirmed a cubic zinc blende structure (F-43m), and a systematic lattice contraction, confirming Se substitution at Te sites. Optical studies revealed a linear bandgap reduction from 1.585 eV to 1.563 eV (similar to 3.7 meV per % Se), consistent with the redshift in photoluminescence emission attributed to intrinsic excitonic recombination. Infrared transmittance remained nearly constant at about 60 %, suggesting good optical uniformity. I-V measurements using Au-Pd ohmic contacts showed a composition dependent increase in resistance, reaching similar to 2 x 10(8) Omega at 4 % Se without intentional donor doping. Magnetic measurements confirmed paramagnetism across all compositions with marginal increase in saturation magnetization and internal coercivity arising from Mn-anion exchange interactions. The results demonstrate that Se alloying enhances electrical resistance while preserving stable paramagnetic behavior, making CdMnTeSe a promising material for room temperature radiation detectors and magneto-optical applications.

We report detailed Raman spectroscopic and magnetic susceptibility studies on the spin-driven ferroelectric compounds Mn4Nb2O9 (MNO) and Mn4Ta2O9 (MTO). Both systems exhibit strong spin-phonon coupling below the short-range magnetic ordering temperature (T(sro)=223 K), followed by further renormalization of several Raman modes at the long-range magnetic ordering temperatures (TN = 120 K for MNO and 110 K for MTO). Pronounced anomalies in Raman mode frequencies and linewidths, along with the emergence of octahedral modes between Tsro and TN, indicate a possible low-symmetry structural transition, more evident in MNO and closely linked to magnetic ordering in MTO. Distinct low-temperature evolutions of Raman mode shift, linewidth, and integrated intensity in MNO and MTO highlight the role of the nonmagnetic B-site cation in tuning spin-lattice coupling, driven by differences in spin-orbit coupling and orbital hybridization between Nb5+ (4d) and Ta5+ (5d). By combining Raman spectroscopy with nuclear magnetic resonance, and diffuse reflectance spectroscopy, we further show that Mn-based systems possess a more distorted local structure than their Co analogues, while their electronic structures differ despite comparable band gaps. These results provide a comprehensive understanding of spin-lattice coupling in Mn- and Co-based A4B2O9 magnetoelectric systems.

Phonon-phonon mode coupling induced by temperature and/or compositional changes has been observed in some materials; however, such behavior is rarely reported under pressure. Here, we report pressure-induced phonon-phonon mode coupling in two orthovanadates Ni3(VO4)2 and Mg3(VO4)2 using high-pressure Raman spectroscopy. In Ni3(VO4)2, pressure-induced phonon-phonon mode coupling is observed between a pair of phonon modes at bending and in the stretching regions. For Mg3(VO4)2, a similar coupling is observed only in the bending region. No structural phase transition is observed in either orthovanadate up to 23.7 GPa. Further, a high-temperature Raman spectroscopic investigation of Ni3(VO4)2 indicated large anharmonicity in the medium-frequency modes, with anomalous true anharmonic contributions for some of the phonon modes.

Though various two-dimensional (2D) materials have been identified as useful candidates for piezoresistive pressure sensors, layered vanadium pentoxide (V2O5) has been negligibly explored. Here, simple drop cast films of ultrasonicated V2O5 on copper (Cu) substrates, stacked face-to-face, are demonstrated to exhibit remarkable piezoresistive pressure sensing behaviour over a pressure range of 250-2000 Pa, as impacted by the growth of copper oxide (CuO) at V2O5/Cu interface. Significant and accelerated growth of CuO at the interface, in ambient conditions, was observed with the addition of deionized (DI) water in the solvent used for drop casting V2O5 films, while it was negligible for those deposited without DI water. The strong growth of CuO interface layer in the former, attributed to the enhanced interaction between V2O5 and Cu in the acidic medium provided by DI water, was found to induce microcracks in V2O5 films. These microcracks could be causing reduced sensitivity of the pressure sensors (similar to 0.36 kPa(-1)) with these films, compared to the sensors with films deposited without DI water (similar to 2.57 kPa(-1)). The results suggest the tunable pressure sensing performance of V2O5 films owing to their readiness to transfer electrons with other materials. In-situ impedance spectroscopic measurements under an applied pressure are also demonstrated, which revealed the major contribution of V2O5/V2O5 interface on sensor response, thereby offering insight into the sensing mechanism. Additionally, V2O5 films are demonstrated as flexible pressure/strain sensors for detecting human physiological activities like finger bending, blinking, swallowing etc.

At ambient pressure and temperature, Raman spectroscopy showed A1, E and T2 modes in HgSe which suggested coexistence of zinc blende (zb) and cinnabar (cin) phase. A blue shift of A1 and E Raman modes was observed with increasing temperature, which was explained by the reduction of lattice constant. Experimental results of Raman spectroscopy were consistent with the DFT calculation, both predicted transition to cin phase at moderate pressure of 1.5-1.8 GPa, and a complete absence of the Raman modes was observed above pressure of 16 GPa, confirming the transformation to the NaCl structure. The pressure-dependent frequency shift, linewidth and Raman intensity was explained by eigenvectors of vibrational symmetry of the modes, anharmonic effect and changes in polarizability.

This study investigates the low-temperature vibrational and magnetic properties, along with the high-pressure structural and vibrational behavior, of the honeycomb magnetoelectric Co4Ta2O9. Raman spectroscopy and magnetic susceptibility measurements reveal pronounced spin-phonon coupling up to '250 K (Tsro), accompanied by local symmetry breaking linked to magnetic short-range order. High-pressure Raman spectroscopy and synchrotron radiation x-ray diffraction identify three isostructural phase transitions at '3, '5.5, and '7.7 GPa, followed by two long-range crystal symmetry transitions at '13 and '18.4 GPa. The first symmetry transition distorts the P-3c1 phase partially into P2/c symmetry, while the second transition introduces an additional monoclinic C2/c phase. These structural transitions align well with our density functional theory based calculations. Partial density of states and Bader charge analyses further reveal charge redistribution between Co and O atoms as a key factor driving the onset of long-range structural transition under high pressure. The stronger renormalization of Raman modes at low temperatures, combined with the lower-pressure structural phase transitions and distinct symmetry sequence compared to the related compound Co4Nb2O9, reflects the enhanced spin-orbit coupling introduced by Ta substitution. Notably, anomalies in Raman mode linewidths and the appearance of new modes [omega(1) and omega(2)] in the 3-7.7 GPa pressure range resemble the low-temperature magnetic behavior, indicating persistence of potential short-range interactions at high pressures. These findings highlight the impact of heavier 5d-Ta compared to 4d-Nb on magnetolattice coupling and pressure-induced phenomena in A4B2O9 (A = Fe, Co, Mn and B = Nb, Ta) systems, offering valuable insights for future research on these materials.

The superior irradiation stability of zirconates compared to titanates has led to an investigation of the Dy2Ti2- xZrxO7 (0 <= x <= 2) series for potential use as control rod materials. The impact of Zr4+ substitution at the Ti4+-site in Dy2Ti2O7, particularly concerning alterations in the crystalline structure and vibrational properties, has been examined using X-ray diffraction and Raman spectroscopy. Zr4+ incorporation retains the pyrochlore-type phase up to a nominal composition of x = 1.2, beyond which a transition to a fluorite phase occurs for x >= 1.6. The increase in relative intensity of Raman band at approximately 600 cm-1 with increasing Zr4+ substitutions indicates an increase in disorder within the pyrochlore-type phases. Additionally, high-temperature X-ray diffraction reveals unusual thermal expansion behaviour in Dy2Ti2-xZrxO7 samples, with thermal expansion coefficients for intermediate compositions exceeding those anticipated by Vegard's law.

Uniform and localized oxide morphologies formed on Zr-2.5(wt.%) Nb alloy in water and steam environments have been studied using electron microscopy techniques such as SEM and EPMA. The uniform oxidation was characterized by a compact and thin oxide layer. In contrast, the nodules showed localized thicker oxide growth with cracked and porous morphology. Significant segregation of Nb at the surface of the oxide nodule was observed, leading to destabilization and spallation of the oxide. The chemical states of Zr, Nb, and O in the two types of oxides were analyzed by XPS. The atomic composition of oxides in terms of O and M fractions was evaluated by p-EBS. The study revealed the oxide nodule to be richer in oxygen in comparison to the surrounding uniform oxide. The phase characteristics of these oxides were studied by Raman spectroscopy. The effect of initial surface in-homogeneities on nodule nucleation has been discussed. Polishing made the surface free of initial in-homogeneities and resulted in uniform oxidation on the surface.

Most reported negative linear compressibility (NLC) materials exhibit either a small NLC over a large pressure range or a high NLC over a very small pressure range. Here, we report the remarkable discovery of giant NLC in the low-temperature form of CuCN (LT-CuCN) over an unusually large pressure range. High-pressure XRD studies on LT-CuCN observed the NLC of -20.5 TPa-1 along the a-axis at zero pressure, and the ambient orthorhombic phase remained stable up to 9.8 GPa. Pressure and temperature-dependent Raman studies identified the phonon vibrations responsible for NLC and negative thermal expansion (NTE).

In this work, we report a high-pressure study on fergusonite-type LaNbO4. Powder x-ray diffraction and Raman spectroscopic experiments support the occurrence of a phase transition between 11 and 14 GPa. The transition takes place from a monoclinic fergusonite-type structure (space group I2/a) to another monoclinic structure (space group P21/c). The phase transition is reversible, and the high-pressure phase is isomorphic to the high-pressure phase of HoNbO4. The high-pressure phase remains stable up to 33.3 GPa, the highest pressure reached in the present measurements. Density-functional theory calculations found that in the pressure range of the studies; the high-pressure phase has a higher enthalpy than the low-pressure fergusonite phase. We propose that the high-pressure phase is metastable and it is observed because of non-hydrostatic conditions in the experiments. The pressure dependence of unit-cell parameters of the low-pressure phase and the room-temperature equation of state are reported. The pressure dependence of various Raman and IR frequencies as obtained from experiment and theory is also reported. For the fergusonite phase, we have also obtained the isothermal compressibility tensor, elastics constants, and elastic moduli.

Uniform and localized oxide morphologies formed on Zr-2.5(wt.%) Nb alloy in water and steam environments have been studied using electron microscopy techniques such as SEM and EPMA. The uniform oxidation was characterized by a compact and thin oxide layer. In contrast, the nodules showed localized thicker oxide growth with cracked and porous morphology. Significant segregation of Nb at the surface of the oxide nodule was observed, leading to destabilization and spallation of the oxide. The chemical states of Zr, Nb, and O in the two types of oxides were analyzed by XPS. The atomic composition of oxides in terms of O and M fractions was evaluated by p-EBS. The study revealed the oxide nodule to be richer in oxygen in comparison to the surrounding uniform oxide. The phase characteristics of these oxides were studied by Raman spectroscopy. The effect of initial surface in-homogeneities on nodule nucleation has been discussed. Polishing made the surface free of initial in-homogeneities and resulted in uniform oxidation on the surface.

In the pursuit of advancing inert matrix fuel (IMF) applications, zirconate pyrochlores have emerged as promising candidates for the incorporation of minor actinides and plutonium. This study employs CeO 2 as a nonradioactive surrogate for PuO 2 and focuses on the synthesis of cerium-substituted Y 2 Zr 2 O 7 samples (Y 2-x Ce x Zr 2 O 7 , 0.0 <= x <= 2.0) through a solid-state route under both reducing and oxidizing conditions to mimic plutonium incorporation. The impact of cerium content and its valence state, which in turn is influenced by synthesis conditions, on crystal structure and phase stability has been investigated through X-ray diffraction and Raman spectroscopic studies. Samples synthesized under reduced conditions undergo a defect fluorite to pyrochlore phase transition through a biphasic mixture consisting of these two phases upon increasing Ce-substitution. Conversely, the high temperature oxidizing synthesis conditions yield a defect fluorite phase field over a wide composition range (0.0 <= x <= 1.6) and a tetragonal phase at x = 2.0. Intriguingly, pyrochlore-type phases obtained under reducing conditions transform into the metastable kappa-phases upon mild oxidation at a relatively low temperature (1073 K), as confirmed by Raman spectroscopic studies. A combination of thermo-gravimetric and Raman spectroscopic investigations confirms the complete reduction of Ce 4 + to Ce 3 + under reducing conditions. The lattice thermal expansion behavior has also been investigated for the defect fluorite phases, synthesized under oxidizing conditions, by means of high temperature XRD spanning the temperature range 298 -1273 K. Notably, the thermal expansion of compositions exhibits an increasing trend with increasing cerium content.

Polarized Raman spectroscopic investigation on oriented single crystal of orthovanadate Co3(VO4)2 is carried out. We have observed and identified symmetries of 32 out of 36 expected Raman active modes of Co3(VO4)2 in different polarization directions. Evolution of frequencies of observed Raman active modes in Co3(VO4)2 are also investigated under variable thermodynamical conditions. The isothermal high pressure Raman spectroscopic investigation indicates stable orthorhombic (Cmca) structure up to 15.7 GPa consistent with reported literature. The isobaric high temperature Raman spectroscopic investigation up to 823 K is used to estimate the total anharmonicity of all the observed Raman active modes. Evolution of Raman spectra indicates structural stability in the temperature and pressure range investigated. By a combination of high pressure and temperature dependent Raman spectroscopic data, the analysis of anharmonicity of observed Raman modes are calculated. Our measurements indicate dominant contribution of three phonon decay process for almost all the observed Raman active modes in Co3(VO4)2. The anharmonicity information along with symmetry of these observed modes can be used as an input in the analysis of expected spin-phonon anomalies around the magnetic transition in Co3(VO4)2 in future investigations.

Uniform and localized oxide morphologies formed on Zr-2.5(wt. %)Nb alloy in water and steam environments have been studied using electron microscopy techniques such as SEM and EPMA. The uniform oxidation was characterized by compact thin oxide layer having smooth oxide-metal interface. In contrast to the uniform oxide, the oxide nodules showed localized thicker oxide growth with cracked and porous morphology. Significant segregation of Nb at the surface of oxide nodule was observed leading to localized spallation of the oxide. The chemical states of Zr, Nb and O in the two types of oxides were analysed by XPS. The atomic composition of oxides in terms of O and M fractions was evaluated by p-EBS. The study revealed higher oxygen to metal fraction in the oxide nodule in comparison to the surrounding uniform oxide. The phase characteristics of these oxides were studied by Raman Spectroscopy. The effect of initial surface in-homogeneities on nodule nucleation has been discussed. Polishing made the surface free of initial in-homogeneities and resulted in uniform oxidation on the surface.

ScVO 4 and ScPO 4 represent the zircon (xenotime) type structures with smallest trivalent cations, and that enable them to host both transition metal and rare-earth ions for applied optical materials. Thus, their crystal chemistry and thermophysical properties becomes relevance for their application in non -ambient conditions. In this report, high temperature crystal chemistry and vibrational properties of ScVO 4 and ScPO 4 , as observed from in situ high temperature powder XRD and Raman spectroscopic studies, are reported. The comparative analyses of the results indicate that, though both are isostructural, they show drastically different thermal expansion behavior. In case of ScVO 4 , the c - axis shows significantly larger expansion compared to a - axis, while in ScPO 4 the thermal expansion along and a and c - axes are more or less similar. At ambient condition, the thermal expansion anisotropy in ScPO 4 and ScVO 4 are 1.02 and 3.97, respectively. Additionally, ScPO 4 shows relatively lower coefficient of volume thermal expansion compared to ScVO 4 , ( alpha v = 23.64 x 10 -6 K -1 for ScPO 4 and 26.09 x 10 -6 K -1 for ScVO 4 ), and is contributed by the expansion of ScO 8 units in their structures. The thermal expansion coefficients of ScO 8 unit in ScPO 4 and ScVO 4 are 36.3 x 10 -6 K -1 and 39.1 x 10 -6 K -1 , respectively. Temperature evolution of Raman modes indicates weakening of all the modes, except a symmetric stretching mode, with increasing temperature. The anharmonic analyses of the Raman modes indicate that implicit contributions in ScVO 4 and ScPO 4 are appreciably higher than the explicit contributions, and hence the changes in mode wavenumbers with volume play dominating role in governing their thermal expansion behaviors. Further, it is concluded that ScPO 4 is characterized by more or less like rigid unit cell compared to ScVO 4 .

Cyclin-dependent kinase 7 (CDK7) has emerged as an exciting target for oncotherapy because it controls both the cell cycle and RNA Pol II-mediated transcription, two critical processes dysregulated in cancer cells. Here, we report the discovery of a novel, orally bioavailable CDK7 early lead inhibitor (BWC 5044) identified through structure-guided drug design. BWC5044 has shown promising results in preclinical efficacy studies, with enhanced anti-tumour activity and improved overall survival rates.

HPK1, a MAP4K family serine/threonine kinase exclusive to hematopoietic cells, plays a pivotal role in dampening TCR and BCR signal cascades. Its functions extend to influencing IL2 secretion, T-cell maturation and migration, tumor infiltration and dendritic cell antigen presentation. Targeting HPK1 with small molecules presents a promising approach to enhance antitumor immunity.