High magnetic field phase diagram and weak FM breaking in (Ni0.93Co0.07)3V2O8

We present magnetostriction and thermal expansion measurements on multiferroic (Ni0.93Co0.07)3V2O8. The high field phase diagrams up to 33 T along the a, b and c directions are built. For H//a, as the magnetic field increases, two intermediate phases appear between the incommensurate phase and the paramagnetic phase at about 7 K, and then a magnetically induced phase appears above the paramagnetic phase. For H//b,thermal expansion measurement indicates a mutation in the spin lattice coupling of the high field phases. The interlaced phase boundary suggests a mixed state in the optical high field phase. For H//c, an intermediate phase between the commensurate phase and the incommensurate phase is detected. A nonlinear boundary between the intermediate phase and the low temperature incommensurate phase, and a clear boundary between the commensurate phase and the paramagnetic phase are found. These results indicate that doping Co2+ breaks the weak ferromagnetic moment of the commensurate phase, which exists in the parent compound Ni3V2O8 and (Ni0.9Co0.1)3V2O8. This nonlinear influence reflects complicated spin modulation in Ni3V2O8 by doping Co2+.Comment: 7 pages, 4 figure

Huge magnetostriction in superconducting single-crystalline BaFe1.908_{1.908}Ni0.092_{0.092}As2_{2}

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe$_{1.908}$Ni$_{0.092}$As$_{2}$ single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10$^{-4}$) was observed in the direction of the twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe$_{1.908}$Ni$_{0.092}$As$_{2}$ can be well explained by a flux-pinning-induced mechanism.Comment: 4 pages, 3 figure

Mechanism and threshold of environmental stressors on seagrass in high-turbidity estuary: case of Zostera japonica in Yellow River Estuary, China

Zostera japonica (Z. japonica), the most widely distributed seagrass species in temperate estuaries, has experienced a dramatic decline of nearly 75% over the past decade. While previous research has investigated the adaptation of seagrass individuals and populations to single stress factors, the molecular mechanisms underlying the interaction of multiple stressors remain poorly understood. This study conducted laboratory experiments to examine the response of Z. japonica at different life stages to environmental pressures, specifically salinity and turbidity, as indicated by changes in free amino acids (FAAs). The results demonstrate that Z. japonica exhibits stronger adaptability to high salinity environments but displays weaker adaptability to freshwater conditions. Through single stress experiments, the salinity and turbidity thresholds for FAA homeostatic disturbance in Z. japonica were determined at seedling, juvenile, and mature stages. As Z. japonica matures, its metabolic pathways expand and diversify, allowing the regulation of key FAAs to enhance stress resistance. Turbidity stress exerts a more pronounced negative impact on the cellular homeostasis of Z. japonica compared to salinity stress, and when turbidity levels exceed 150 NTU, they significantly intensify the negative effects of salinity stress on the seagrass. Furthermore, under strong salinity-turbidity interactions, the concentration of key FAAs generally decreases by 20-30%, indicating inhibition of growth and development in Z. japonica. These findings have important implications for the conservation of intertidal seagrass beds and estuarine ecosystems in the face of multiple human activities and environmental stressors. The study provides valuable insights into the molecular mechanisms underlying Z. japonica’s adaptations to salinity and turbidity stress, contributing to the development of targeted strategies to mitigate the impacts of environmental pressures on seagrass populations and promote the resilience of these critical marine ecosystems