Spray pyrolysis-derived robust ferroelectric BiFeO3 thin films.

Scalable and low-cost synthesis of high-quality ferroic films is critical for the development of advanced electronic devices and sensors. Here, we employ solution-based spray pyrolysis to fabricate bismuth ferrite thin films on glass substrates and explore the impact of annealing conditions to attain functional thin films of superior quality and switchable polarization. Optimised thin films display polycrystalline nanostructured grains with the highest X-ray diffraction intensity along the (110) orientation and a mixed Fe2+/3+ valence suggesting the presence of oxygen vacancies. The optimized films show a complex ferroelectric domain microstructure and exhibit robust nanoscale polarization switching in the range of several volts. Domains are found to scale with the sizes of nanocrystalline grains, which points to the role of surface-energy-related mechanisms affecting the domain patterns. Our results demonstrate the potential of spray pyrolysis for the fabrication of high-quality ferroelectric thin films and provide new opportunities for the development of low-cost scalable advanced electronic devices.

Correction: Sizable magnetic entropy change in bismuth-substituted La0.75Bi0.1Na0.15MnO3 manganite.

Correction for 'Sizable magnetic entropy change in bismuth-substituted La0.75Bi0.1Na0.15MnO3 manganite' by Lozil Denzil Mendonca et al., Phys. Chem. Chem. Phys., 2022, 24, 13171-13188, https://doi.org/10.1039/D2CP00559J.

Sizable magnetic entropy change in bismuth-substituted La0.75Bi0.1Na0.15MnO3 manganite.

The bismuth (Bi)-substituted La0.85-xBixNa0.15MnO3 (x = 0 and x = 0.1) manganites have been investigated for achieving room temperature magnetic entropy change at low magnetizing intensities. A 10% Bi ion substitution at the La site has led to the relatively higher symmetry R3̄c rhombohedral structure showing improvement in Mn-O-Mn bond angles. The chemical additive Bi2O3 has assisted in grain growth to form densified specimens even at low sintering temperatures. The sample has a soft ferromagnetic nature with a single magnetic transition occurring at 275 K. Phenomenal improvement in magnetic sensitivity at low magnetic fields was achieved with TC close to room temperature. Nearly 100-500 percent increases in magnetic entropy change was realised over existing parent compounds and the entropy changes are greater than the prototype, Gd of active magnetic refrigeration. The magnetic interactions are governed by the Tri-Critical Mean Field model with emphasis on the coexistence of long-range and short-range interactions. The characteristics, viz. soft ferromagnet of second-order phase transition, abrupt phase change at TC, the resultant large magnetic entropy change of 4.4 J kg-1 K-1 and temperature averaged entropy change of 3.914 J kg-1 K-1 (10 K) at the low magnetic field of 1.5 T are expected to facilitate application prospects as a magnetic refrigerants for room temperature working range.

Curcumin nanocrystals attenuate cyclophosphamide-induced testicular toxicity in mice.

The cancer therapy using cyclophosphamide (CP) has been associated with adverse effects on the testicular function that raises concerns about the future fertility potential among cancer survivors. Curcumin, a polyphenol, has shown to possess a plethora of biological functions including tissue protective effects. In the present study, we investigated the protective effects of curcumin nanocrystals (NC) in mitigation of CP-induced testicular toxicity. Healthy adult (8-10 week) and prepubertal (2 week) male Swiss albino mice were injected with a single dose of CP (200 mg/kg) intraperitoneally (i.p). NC (4 mg/kg, i.p.) was administered every alternate day, for 35 days in adult mice while, a single dose of NC was injected intraperitoneally to prepubertal mice 1 h prior to CP. Administration of multiple doses of NC ameliorated CP-induced testicular toxicity in adult mice, which was evident from the improved sperm functional competence, sperm chromatin condensation, seminiferous tubule architecture and decreased apoptosis in testicular cells. Further, administration of NC 1 h prior to CP in prepubertal mice modulated the expression of genes pertaining to proliferation, pluripotency, DNA damage and DNA repair in spermatogonial cells at 24 h after the treatment. Overall, these results suggest that NC could be a promising chemoprotective agent, which can have potential application in male fertility preservation.

The room temperature inflection of magnetism and anomalous thermoelectric power in lacunar compounds of La0.85-xBixK0.15MnO3.

This study focuses on the effects of the substitution of a nonmagnetic ion on the structure, magnetism, and thermoelectric power of binary La0.85-xBixK0.15MnO3 (x = 0, 0.15, 0.3) manganites synthesized via a ceramic route. Structural analysis reveals a dual crystallographic phase in the system, which results due to charge disproportionation. The consequent segregation of Mn3O4 grains is revealed via field-emission scanning electron microscopy images. Magnetically, the specimens have a second-order phase transition nature, and a Curie temperature (TC) is interestingly observed at room temperature (∼300 K) in the x = 0 compound. The variation of TC is discussed in light of a combined contribution from a lacuna and the 6s2 lone pair of bismuth. The presence of a Griffiths singularity in all specimens is realized due to ferromagnetic clusters appearing in the paramagnetic matrix. The generation of Mn2+ ions due to charge disproportionation and consequent changes observed in the magnetic and thermoelectric power behaviour are discussed considering multiple hopping and direct hopping between Mn3+, Mn2+, and Mn4+ ions. A phenomenological model is exploited to obtain the thermomagnetic parameters. The magnon drag and phonon drag largely decide the thermoelectric power in the low-temperature ferromagnetic region, whereas the small polaron hopping of carriers contributes to the TEP in the high-temperature paramagnetic region. A colossal TEP value of -800 µV K-1 is observed at around 14 K for the x = 0.3 sample.