Nanomechanical probing and strain tuning of the Curie temperature in suspended Cr₂Ge₂Te₆-based heterostructures

Two-dimensional magnetic materials with strong magnetostriction are attractive systems for realizing strain-tuning of the magnetization in spintronic and nanomagnetic devices. This requires an understanding of the magneto-mechanical coupling in these materials. In this work, we suspend thin Cr2Ge2Te6 layers and their heterostructures, creating ferromagnetic nanomechanical membrane resonators. We probe their mechanical and magnetic properties as a function of temperature and strain by observing magneto-elastic signatures in the temperature-dependent resonance frequency near the Curie temperature, TC. We compensate for the negative thermal expansion coefficient of Cr2Ge2Te6 by fabricating heterostructures with thin layers of WSe2 and antiferromagnetic FePS3, which have positive thermal expansion coefficients. Thus we demonstrate the possibility of probing multiple magnetic phase transitions in a single heterostructure. Finally, we demonstrate a strain-induced enhancement of TC in a suspended Cr2Ge2Te6-based heterostructure by 2.5 ± 0.6 K by applying a strain of 0.026% via electrostatic force.QN/Steeneken LabQN/vanderSarlabQN/van der Zant LabDynamics of Micro and Nano System

Soil-Based Treatments of Mechanically Collected Cyanobacterial Blooms from Lake Taihu: Efficiencies and Potential Risks

In China, mechanical collection of cyanoblooms followed by soil-based treatments has been widely used as emergency strategies in many eutrophicated freshwaters. This study was to evaluate both efficiencies and potential risks of typical soil-based technologies. Results from this study indicated that over 90% of cyanobacterial biomass and 96% of dissolved microcystins (MCs) could be restrained in soils via three-level systems, which were much better than single-level systems. High concentrations of MCs, ranged from 65 to 276 ng g(-1) and from 2.12 to 6.6 ng g(-1), were found in soils around treatment systems and croplands, respectively. In the soil solutions, MCs ranged from 0.35 to 2.0 mu g L-1, showing a potentially high leaching risk. In the samples from shallow groundwater near the treatment systems, MC concentrations were detected as high as 1.2 mu g L-1. Moreover, bioaccumulations of MCs varied between 22 and 365 mu g kg(-1), and 19-222 mu g kg(-1) were found in 13 kinds of crops and 7 kinds of wild grass, respectively. Our results indicated for the first time that current soil-based technologies were effective but could pose potential environmental, ecological, and public health risks. Further improvements of these technologies were also proposed based on our findings.In China, mechanical collection of cyanoblooms followed by soil-based treatments has been widely used as emergency strategies in many eutrophicated freshwaters. This study was to evaluate both efficiencies and potential risks of typical soil-based technologies. Results from this study indicated that over 90% of cyanobacterial biomass and 96% of dissolved microcystins (MCs) could be restrained in soils via three-level systems, which were much better than single-level systems. High concentrations of MCs, ranged from 65 to 276 ng g(-1) and from 2.12 to 6.6 ng g(-1), were found in soils around treatment systems and croplands, respectively. In the soil solutions, MCs ranged from 0.35 to 2.0 mu g L-1, showing a potentially high leaching risk. In the samples from shallow groundwater near the treatment systems, MC concentrations were detected as high as 1.2 mu g L-1. Moreover, bioaccumulations of MCs varied between 22 and 365 mu g kg(-1), and 19-222 mu g kg(-1) were found in 13 kinds of crops and 7 kinds of wild grass, respectively. Our results indicated for the first time that current soil-based technologies were effective but could pose potential environmental, ecological, and public health risks. Further improvements of these technologies were also proposed based on our findings