Enhanced spin accumulation at room temperature in graphene spin valves with amorphous carbon interfacial layers

We demonstrate a large enhancement of the spin accumulation in monolayer graphene following electron-beam induced deposition of an amorphous carbon layer at the ferromagnet-graphene interface. The enhancement is 10^4-fold when graphene is deposited onto poly(methyl metacrylate) (PMMA) and exposed with sufficient electron-beam dose to cross-link the PMMA, and 10^3-fold when graphene is deposited directly onto SiO2 and exposed with identical dose. We attribute the difference to a more efficient carbon deposition in the former case due to an increase in the presence of compounds containing carbon, which are released by the PMMA. The amorphous carbon interface can sustain very large current densities without degrading, which leads to very large spin accumulations exceeding 500 microeVs at room temperature

Microscopic Theory of Magnon-Drag Thermoelectric Transport in Ferromagnetic Metals

A theoretical study of the magnon-drag Peltier and Seebeck effects in ferromagnetic metals is presented. A magnon heat current is described perturbatively from the microscopic viewpoint with respect to electron--magnon interactions and the electric field. Then, the magnon-drag Peltier coefficient \Pi_\MAG is obtained as the ratio between the magnon heat current and the electric charge current. We show that \Pi_\MAG=C_\MAG T^{5/2} at a low temperature $T$; that the coefficient C_\MAG is proportional to the spin polarization $P$ of the electric conductivity; and that $P>0$ for C_\MAG<0, but $P0$. From experimental results for magnon-drag Peltier effects, we estimate that the strength of the electron--magnon interaction is about 0.3 eV$\cdot\AA^{3/2}$ for permalloy.Comment: 3 pages, 2 figures, accepted for publication in Journal of the Physical Society of Japa

Evaluation of the effectiveness of some acaricides in the control of the two-spotted spider mite (Tetranychus urticae Koch) on squash crops under high plastic tunnels

The two-spotted spider mite (Tetranychus urticae Koch) is an important pest present in squash crops under high plastic tunnels and in the field, that can reduce yield quantitatively and depreciating it qualitatively. The attack is frequent in dry and hot years, reaching a maximum development in the months of July-August. On the leaves, following the attack, depigmentations appear followed by their drying. The experiment done in 2023, aimed to evaluate the effectiveness of two products based on Neem oil (Oleorgan) and hexythiazox (Nissorun 10 WP) for controlling the pest on squash crops. The 'Perfect' cultivar and the 'Lorea' hybrid were used as biological material. The yield on variants and replicates was recorded, being between 12.30 and 22.58 t/ha. Based on the obtained results, the efficacy (%) was calculated and was between 64.4 and 96.0%

Statin therapy in patients with diabetes and hepatitis C

The objective of this study was to determine the effects of statin therapy (atorvastatin) on serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in patients with type 2 diabetes mellitus (T2DM) and chronic hepatitis C (CHC). A number of 77 patients with T2DM and CHC were selected, treated with atorvastatin, 20 mg, for 6 months, who underwent anthropometric measurements and biochemical tests (including fasting serum glucose, lipid profile, liver profile, cytokines profile) at baseline, after 1 month (clinical and biochemical profile for safety) and after 6 months of treatment. The patients’ average age was 52.53±9.7 years. Plasma low-density lipoprotein cholesterol (LDL-C) (-32.4 mg/dL), triglycerides (-29.7 mg/dL), total cholesterol (-32.8 mg/dL) decreased (p<0.05), and high-density lipoprotein cholesterol (HDL-C) (+3.04 mg/dL) increased (p<0.05), after 6 months. Atorvastatin treatment was associated with decreases of AST, ALT, and also leptin and interleukin-6 (IL-6) levels (all p<0.05) but we did not find any effect on plasma tumor necrosis factor-alpha (TNF-α) (p=0.119). Atorvastatin was an effective and well tolerated treatment for lowering total cholesterol, LDL-C, triglycerides in patients with CHC. Among patients with CHC there was no significant elevation of liver enzymes during statin treatment, and we even noticed an improvement of hepatic profile

Multi-Cloud Portable Application Deployment with VEP

Leveraging the plethora of available Infrastructure-as-a-Service (IaaS) solutions proves to be a hard task for users who should face the complexity of dealing with heterogeneous systems, either in terms of resources or APIs. Application portability is the mean to reduce the burden of adapting applications for specific IaaS types and escape po-tential vendor lock-in. The Virtual Execution Platform (VEP) is a cloud middleware software that interfaces multiple IaaS clouds and presents end-users with an interface facilitating deployment and life cycle man-agement of distributed applications made up of several inter-networked virtual machines. This paper presents the design of VEP and experi-mental results that evaluate its scalability in deploying applications on OpenNebula and OpenStack clouds

Bloch-Wall Phase Transition in the Spherical Model

The temperature-induced second-order phase transition from Bloch to linear (Ising-like) domain walls in uniaxial ferromagnets is investigated for the model of D-component classical spin vectors in the limit D \to \infty. This exactly soluble model is equivalent to the standard spherical model in the homogeneous case, but deviates from it and is free from unphysical behavior in a general inhomogeneous situation. It is shown that the thermal fluctuations of the transverse magnetization in the wall (the Bloch-wall order parameter) result in the diminishing of the wall transition temperature T_B in comparison to its mean-field value, thus favouring the existence of linear walls. For finite values of T_B an additional anisotropy in the basis plane x,y is required; in purely uniaxial ferromagnets a domain wall behaves like a 2-dimensional system with a continuous spin symmetry and does not order into the Bloch one.Comment: 16 pages, 2 figure

Ferromagnetic resonance assisted optomechanical magnetometer

The resonant enhancement of mechanical and optical interaction in optomechanical cavities enables their use as extremely sensitive displacement and force detectors. In this work we demonstrate a hybrid magnetometer that exploits the coupling between the resonant excitation of spin waves in a ferromagnetic insulator and the resonant excitation of the breathing mechanical modes of a glass microsphere deposited on top. The interaction is mediated by magnetostriction in the ferromagnetic material and the consequent mechanical driving of the microsphere. The magnetometer response thus relies on the spectral overlap between the ferromagnetic resonance and the mechanical modes of the sphere, leading to a peak sensitivity better than 900 pT Hz$^{-1/2}$ at 206 MHz when the overlap is maximized. By externally tuning the ferromagnetic resonance frequency with a static magnetic field we demonstrate sensitivity values at resonance around a few nT Hz$^{-1/2}$ up to the GHz range. Our results show that our hybrid system can be used to build high-speed sensor of oscillating magnetic fields