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Superheating-assisted melting and crystallization are prominent subjects in condensed matter physics. However, understanding the superheating concepts under acoustic shocked conditions remains a mystery. Herein, we demonstrate superheating on the basis of dynamic recrystallization in a D -tartaric acid powder sample, which nearly attains an ideal crystal structure and morphology under the 100-shocked conditions compared to the control sample and the obtained results are evaluated by conventional diffraction, spectroscopic and microscopic techniques. From the XRD results, the intensities of the planes (100) and (110) are found to have increased under the 100-shocked conditions, whereas the intensity ratio (011)/(110) has been significantly reduced. Moreover, the intensity ratio of major internal Raman modes such as vC–O (1694 and 1700 cm−1), vC–H (2933 and 2967 cm−1) and vO–H (3331 and 3403 cm−1) has been considerably modified with respect to the number of shock pulses such that the sample produces an ideal Raman spectrum of D -tartaric acid, and thereby the intensities of the lattice Raman modes also support this claim. Most importantly, the SEM results demonstrate the formation of an ideal morphology of D -tartaric acid from the irregular morphological pattern upon exposure to 100 shocks due to the superheating and dynamic recrystallization process. The proposed technique is strongly suggested for materials processing to enhance technological significance for all classes and scales of materials. [ABSTRACT FROM AUTHOR]

Achieving facile and simple temperature- and pressure-induced transformation of sp2-to-sp3 remains an important and fascinating challenge within the realm of carbon science and technology. Here, we introduce a new technique that utilizes repeated exposure of low-pressure (2.0 MPa) millisecond acoustic shock waves on a sample to facilitate the successful transformation of sp2-to-sp3 carbon bonds. This transformation is verified through visible Raman spectroscopic, X-ray photoelectron spectroscopic (XPS), and high-resolution transmission electron microscopic (HRTEM) observations. Typically, in general nanosecond dynamic compression experiments, sp3 carbon bond formation occurs only at pressures of ∼45 GPa or more, and under static compression, this transition takes place at ∼30 GPa. However, with our innovative approach, similar results can be achieved with acoustic shock waves operating at significantly lower pressures of 2.0 MPa. Based on the observed analytical results, the sp2-to-sp3 type phase transition occurred at the 500-shocked condition and this transition leads to the conversion of layered crystalline graphite to non-layered amorphous graphite, which may be the pre-state of sp3 bonded diamond formation. The complete disappearance of the 2D band in the Raman spectrum and the conversion of asymmetric to symmetric shape of the C 1s band in the XPS spectrum are the major proof for the proposed sp2-to-sp3 phase transition. Further optimization is currently underway to find the critical point in achieving the probable phase transition of graphite to diamond. The proposed technique put forward a platform for a new impending way to make the sp3 carbons from sp2 carbons in indoor laboratories, which may also offer a new science division to understand the formation of diamonds or diamond-like structures under lower transient pressure conditions. Even though the proposed technique is cost-effective and involves a handy tool, to move it from lab to industrial applications, we still have a lot of ground to cover in fundamental aspects. [ABSTRACT FROM AUTHOR]

Amino acids are among the earliest organic molecules to exist on Earth, and the origin of such bio-molecules on Earth is still a topic of intense discussion in the associated scientific area. In this regard, one of the crucial methods to investigate this subject and to better comprehend the emergence of biomolecules on the planet is to carry out indoor laboratory-size shock wave recovery experiments. In this instance, we have investigated the structural and morphological properties of L -serine powder samples processed using acoustic shock waves. The effects of shock waves on the title sample have been studied using conventional diffraction and microscopy methods. According to the diffraction results, under shocked conditions, there has been no crystallographic phase change observed, whereas the entire test samples have undergone dynamic recrystallization with the same P212121 space group. Shock wave-driven dynamic recrystallization theories can explain the observed surface changes on the test samples, which underwent considerable surface modifications under shocked conditions. [ABSTRACT FROM AUTHOR]

We present our findings on the room temperature (RT) soft ferromagnetism (FM) of the sol-gel-prepared Co-doped barium titanate (BaTiO3) nanoparticles with two distinct Co concentrations (0.25 mol% and 0.5 mol%), that is appropriate for spintronic applications as evidenced by experimental observations. X-ray diffraction investigation revealed that the produced samples, which had diameters less than 100 nm, belonged to the pseudo-cubic phase of the BaTiO3 structure and did not exhibit any signs of the Co cluster or any other Co oxides. UV-visible absorption spectra demonstrate that the optical response is red shifted and the bandgap energy is lowered when Co is incorporated into the BaTiO3 lattice. The inclusion of cobalt ions may have brought about a change in size or an increase in surface defects, as evidenced by the PL spectra, which show that the intensity of emission peaks changes as the dopant concentration increases. In the 0.25 mol% Co-doped BaTiO3 sample, the FM behavior is clearly visible along with the paramagnetic (PM) phase at RT. Significantly, it becomes apparent that as the doping concentration is raised to 0.5 mol%, the saturation magnetization is reduced, and a pure phase of soft FM is obtained. This soft FM feature witnessed in 0.5 mol% doped BaTiO3 with low coercivity (96.8 Oe) and low saturation magnetization (9.7 × 10−3 emu/g) is likely due to oxygen vacancies and could set out as a promising magnetic material for possible spintronic applications. [ABSTRACT FROM AUTHOR]