New Publication: Electrical Detection of DC Spin Current Propagation Through an Epitaxial Antiferromagnetic NiO Layer

David Newman

Congratulations to third year PGR David Newman, whose paper ‘Electrical Detection of DC Spin Current Propagation Through an Epitaxial Antiferromagnetic NiO Layer’ has recently been published in IEEE Transactions on Magnetics.

David explains this work and the impact of its findings:

Spin currents (net transfer of spin angular momentum) have been suggested as potential successors to charge currents in areas like magnetic data storage. A spin current can be generated by a mechanism known as ‘spin pumping’ whereby a ferromagnetic (FM) layer is excited into resonance and then ‘pumps’ a spin current into an adjacent nonmagnetic (NM) layer. Recently, work has even found that antiferromagnetic (AFM) layers could even be used to amplify the amount of spin current produced.

 

The main issue comes with the difficulty in observing a pure spin current. Current techniques mainly consist of detecting the spin transfer torque exerted on an additional FM layer (AC spin current). Alternatively, the DC spin current can be observed by the transverse charge current generated by a spin current propagating through a heavy metal (like Pt) via the inverse spin Hall effect (ISHE).

 

In our work, we measure the ISHE on a sample with an AFM layer where the AC spin current has already been detected (see separate publication: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.217201) and, with some experimental considerations, extract the DC spin current. By showing AC and DC spin current components can be observed in the same sample, this work provides the pathway to a more complete perspective of spin current propagation through an AFM layer which is important in the development of spintronic technologies in areas such as magnetic data storage.

New Publication: Graphene coated fabrics by ultrasonic spray coating for wearable electronics and smart textiles

Kavya Sadanandan

Congratulations to third year PGR Kavya Sadanandan, whose paper ‘Graphene coated fabrics by ultrasonic spray coating for wearable electronics and smart textiles’ was recently published in Journal of Physics: Materials.

Abstract

The seamless incorporation of electronics in textiles have the potential to enable various applications ranging from sensors for the internet of things to personalised medicine and human-machine interfacing. Graphene electronic textiles are a current focus for the research community due to the exceptional electrical and optical properties combined with the high flexibility of this material, which makes it the most effective strategy to achieve ultimate mechanical robustness of electronic devices for textile integrated electronics. An efficient way to create electronic textiles is to fabricate devices directly on the fabric. This can be done by coating the textile fabric with graphene to make it conductive. Here we discuss successful and efficient methods for coating graphene nanoplatelets on textile substrates of nylon, polyester and meta-aramid using ultrasonic spray coating technique. These coatings are characterised by scanning electron microscopy, contact angle and electrical conductivity measurements in order to identify the optimal textile electrode.  Our study provides the foundation for the large-area fabrication of graphene electronic textiles.

New Publication: Bimetal-organic framework derived multi-heterostructured TiO2/CuxO/C nanocomposites with superior photocatalytic H2 generation performance

Congratulations to final year PGR Zahid Hussain for his new publication ‘Bimetal-organic framework derived multi-heterostructured TiO2/CuxO/C nanocomposites with superior photocatalytic H2 generation performance’, which was recently published in Journal of Materials Chemistry A (JMCA).

In this work, In-situ formation of p-n heterojunctions between TiO2 and CuxO in heteroatoms-doped carbon nanocomposites and their applications in photocatalytic H2 evolution were demonstrated. One-step pyrolysis of bimetal-organic-frameworks NH2-MIL-125(Ti/Cu) in water steam at 700 ºC forms phasejunction between nitrogen/carbon co-doped anatase and rutile TiO2, accompanied by the formation of CuxO heterostructures. Moreover, p-n heterojunction is also formed between TiO2/CuxO nanoparticles. These multi-heterostructures are embedded in N-containing and hydrophilic carboxyl functionalised carbon. The optimised TiO2/CuxO/C composites absorb more visible light and offer multiple pathways for photoinduced electrons and holes migration. Also, these nanocomposites provide increased active sites for photocatalytic reactions. Without loading expensive noble metals, TiO2/CuxO/C nanocomposites exhibited superior photocatalytic H2 generation activity of 3298 µmol gcat-1 h-1 under UV-Visible light, 40 times higher than commercial TiO2. This work offers a simple approach to fabricate novel photocatalytic nanocomposites for efficient H2 generation.

Zahid’s previous publications include a translation of Carlo Rovelli’s “Seven Brief Lessons on Physics” into Urdu and ‘Surface functionalized N-C-TiO2/C nanocomposites derived from metal-organic framework in water vapour for enhanced photocatalytic H2 generation’ , of which he was lead author, published in Journal of Energy Chemistry.