Heteroepitaxy of Co-Based Heusler Compound/Muscovite for Flexible Spintronics

Investigating Anisotropic Magnetoresistance in Epitaxially Strained CoFe Thin Films on a Flexible Mica

This study investigates the crystal structure, epitaxial relation, and magnetic properties in CoFe thin films deposited on a flexible mica substrate. The epitaxial growth of CoFe thin films was successfully achieved by DC magnetron sputtering, forming three CoFe(002) domains exhibiting four-fold symmetry on the mica substrate. A notable achievement of this work was the attainment of the highest anisotropic magnetoresistance (AMR) value reported to date on a flexible substrate. Additionally, it was observed that the magnetic characteristics of the CoFe films on the flexible mica substrate display reversibility upon strain release. More importantly, the AMR effect of epitaxial CoFe films on flexible mica shows lesser dependence on the crystalline orientation and remains the same under different bending states. These findings demonstrate the potential of utilizing CoFe films on flexible substrates to develop wearable magnetoresistance sensors with diverse applications.

Functionalized Co2FeAl Nanoparticles for Detection of SARS CoV-2 Based on Reverse Transcriptase Loop-Mediated Isothermal Amplification

Loop-mediated isothermal amplification (LAMP) is a sensitive, efficient, and rapid nucleic acid amplification technique resulting in a large number of amplicons; however, it suffers from a high incidence of false positives due to carry-over and aerosol. Herein, we report a 10 min nano-capture system that is used in conjunction with a modified reverse transcriptase-LAMP (RT-LAMP) assay for the accurate detection of SARS CoV-2 virus. The nano-capture system employs in-house-designed probe-functionalized magnetic nanoparticles Co2FeAl (cobalt-based Heusler alloy) for efficient capture of contaminating amplicons from the reaction mixture preceding RT-LAMP. The nano-cleaned RT-LAMP assay along with engineered primers successfully detected the presence of 10 copies of SARS CoV-2 virus while completely eliminating the incidence of false positives. The presented contaminant-capture method has been compared with other approaches for elimination of contaminants and was found to be more effective. The insight brought in this work is the design of a rapid nano-capture system that hybridizes with contaminating amplicons (carry-over) with high specificity to enable easy removal from the assay for elimination of false positives. The method has been proven to be successful for RT-LAMP assays in the rapid and highly specific detection of SARS CoV-2, which is currently a major challenge for global health. To the best of our knowledge, this is the first work involving a nano-based cleaning strategy for reliable and rapid diagnosis using isothermal amplification approaches.

van der Waals oxide heteroepitaxy for soft transparent electronics

The quest for multifunctional, low-power and environment friendly electronics has brought research on materials to the forefront. For instance, as the emerging field of transparent flexible electronics is set to greatly impact our daily lives, more stringent requirements are being imposed on functional materials. Inherently flexible polymers and metal foil templates have yielded limited success due to their incompatible high-temperature growth and non-transparency, respectively. Although the epitaxial-transfer strategy has shown promising results, it suffers from tedious and complicated lift-off-transfer processes. The advent of graphene, in particular, and 2D layered materials, in general, with ultrathin scalability has revolutionized this field. Herein, we review the direct growth of epitaxial functional oxides on flexible transparent mica substrates via van der Waals heteroepitaxy, which mitigates misfit strain and substrate clamping for soft transparent electronics applications. Recent advances in practical applications of flexible and transparent electronic elements are discussed. Finally, several important directions, challenges and perspectives for commercialization are also outlined. We anticipate that this promising strategy to build transparent flexible optoelectronic devices and improve their performance will open up new avenues for researchers to explore.

Flexible Antiferromagnetic FeRh Tapes as Memory Elements

The antiferromagnetic to ferromagnetic transition occurring above room temperature in FeRh is attracting interest for applications in spintronics, with perspectives for robust and untraceable data storage. Here, we show that FeRh films can be grown on a flexible metallic substrate (tape shaped), coated with a textured rock-salt MgO layer, suitable for large-scale applications. The FeRh tape displays a sharp antiferromagnetic to ferromagnetic transition at about 90 °C. Its magnetic properties are preserved by bending (radii of 300 mm), and their anisotropic magnetoresistance (up to 0.05%) is used to illustrate data writing/reading capability.