Oxidation can strongly influence the performance of Cu nanowires (CuNWs) by decreasing their conductivity. Here, we identify and investigate a way to prevent the oxidation process of CuNWs to maintain the high conducting performance of CuNWs as transparent electrodes. CuNWs were synthesised using an aqueous method. We prepared several temperature treatments (from 0–300 °C) to represent oxidation of CuNWs in different environments, to study the oxidation process and changes in morphology in detail. Depending on the temperature, smooth and uniform CuNWs exposed to oxidation produced rough Cu2O and CuO nanowires. We then suggest a method of protecting nanowires from oxidation, using the Mayer rod coating method to apply a layer of PEDOT:PSS to a transparent conducting film of CuNWs. The result indicates that this method of protection can protect the film, and maintain a stable, and constant resistance over of time, without effecting the excellent conductivity properties of pure CuNWs.
Core–shell Fe3O4@Ag magnetic nanoparticles (MNPs) integrated with a Wheatstone bridge-giant magnetoresistance (GMR) sensor provide access to GMR-based biosensors. The Fe3O4 nanoparticles synthesized using the coprecipitation method demonstrated 77 emu g−1 of magnetization saturation (M
S), 51 Oe of coercivity (H
C), and particle size of 11 nm. Furthermore, core–shell Fe3O4@Ag MNPs prepared by the aqua-solution method possessed 53 emu g−1 of M
S, 145 Oe of H
C, and 17 nm of particle size. This high M
S of nanoparticles not only offer a large induced magnetic field but is sufficient for particle penetration within the biofilms. It was discovered that the sensor can distinguish between the bare Fe3O4 with the Fe3O4@Ag nanoparticles through an output voltage increase corresponding to a decrease in M
S. The output signal of the sensor responds linearly to an increase in the core–shell Fe3O4@Ag nanoparticle concentration, owing to an increase in the induced-field. The sensor exhibits better sensitivity when applied in detecting less than 2 g L−1 of nanoparticle concentration, that is, 0.76 mV per unit of concentration (g/L).
The ability to control the spin textures in semiconductors is a fundamental step toward novel spintronic devices, while seeking desirable materials exhibiting persistent spin texture (PST) remains a key challenge. The PST is the property of materials preserving a unidirectional spin orientation in the momentum space, which has been predicted to support an extraordinarily long spin lifetime of carriers. Herein, by using first-principles density functional theory calculations, we report the emergence of the PST in the two-dimensional (2D) germanium monochalcogenides (GeMC). By considering two stable formation of the 2D GeMC, namely the pure GeX and Janus Ge 2 XY monolayers (X, Y = S, Se, and Te), we observed the PST around the valence band maximum where the spin orientation is enforced by the lower point group symmetry of the crystal. In the case of the pure GeX monolayers, we found that the PST is characterized by fully out-of-plane spin orientation protected by C 2v point group, while the canted PST in the y-z plane is observed in the case of the Janus Ge 2 XY monolayers due to the lowering symmetry into C s point group. More importantly, we find large spin-orbit coupling (SOC) parameters in which the PST sustains, which could be effectively tuned by in-plane strain. The large SOC parameter observed in the present systems leads to the small wavelength of the spatially periodic mode of the spin polarization, which is promising for realization of the short spin channel in the spin Hall transistor devices.
The availability of rapid-portable instruments to monitor the bovine serum albumin (BSA) concentration is vital in the early detection of disease. In this research, an original biosensing method based on a spin-valve giant magnetoresistance as a transducer and magnetite@silver core-shell magnetic nanoparticles (MNPs) as a tag has been proposed for detecting BSA. The synthesized magnetite@silver MNPs tag size is ≈15 nm with ≈52 emu g −1 of saturation magnetization. This proposed biosensor performs rapid detection of BSA through the shifting of the switching magnetic field and the increasing of the output voltage. The effectivity of the sensor in monitoring the BSA concentration was shown by a strong linear correlation with ≈0.06 mV/(mg/ml) of the sensitivity and ≈0.44 mg ml −1 of the detection limit. Moreover, the measurement result can be acquired rapidly up to 1 min with low external magnetic field assistance. Therefore, this biosensing technique can be promoted as a real-time portable biosensor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.