Training and other events: April 2021 to June 2021

Please find below a table of all upcoming XM² training and other events from April 2021 to June 2021, as far as planning currently allows and subject to change.

PGRs, please highlight any XM²-training related absence times to your supervisors. In regards to annual leave or other absence time planning: all confirmed events have been sent to the PGRs via an Outlook calendar invitation, but please ensure to check the CDT in Metamaterials Outlook calendar and to liaise with your supervisors and the CDT in Metamaterials office (metamaterials@exeter.ac.uk) for approval BEFORE you make any bookings, as there might be a few more events coming up that are yet to be confirmed.

Supervisors, please be mindful of the XM² events when setting expectations on research deliverables with the PGRs.

After six months, (e.g. after the Month 6 project is complete), first year PGRs can undertake teaching and demonstrating, provided that they complete LTHE online training first. The course is self-paced so you can take it whenever you like but please note it is mandatory and you will not be able to undertake teaching and demonstrating until you have completed it.

April
15.04.21 Cohort 5 meeting with Alastair and Anja 3rd years 09:00-10:00 via Teams
15.04.21 Introduction to Open Access/Symplectic and Research Data Management 1st years, optional for 2nd and 3rd years 10:00-11:30 via Teams
15.04.21 Cohort 7 meeting with Alastair and Anja 1st years 15:00-17:00 via Teams
19.04.21 Cohort 6 meeting with Alastair and Anja 2nd years 11:00-12:00 via Teams
19.04.21 Cohort 4 meeting with Alastair and Anja 4th years 13:30-14:30 via Teams
30.04.21 Metamaterials Colloquium: Dr Mariana Medina Sanchez, Leibniz Institute for Solid State and Materials Research, ‘Physical and Biohybrid Microrobots for Biomedical Applications’ All PGRs 12:30-13:30 via Zoom
May
28.05.21 Metamaterials Colloquium: Prof. Montserrat Rivas, University of Oviedo, ‘A New Generation of Rapid Diagnostic Tests: The Role of Magnetic Nanoparticles’ All PGRs 12:30-13:30 TBC
June
16.06.21 Project Management (Day 1) 1st years 09:30-16:30 TBC
17.06.21 Project Management (Day 2) 1st years 09:30-16:30 TBC
18.06.21 Beyond a PhD: Dr Al Lambourne, Materials Research Engineer at Rolls Royce All PGRs 12:30-13:30 TBC

 

Zahid Hussain passes his viva!

Zahid Hussain

Congratulations to PGR Zahid Hussain, who has passed his viva. His thesis was titled ‘Metal-organic Framework (MOFs) Derived Nanocomposites: Synthesis and Applications in Photocatalysis’. During his time with the CDT, Zahid published 11 papers, plus an English-to-Urdu translation of Seven Brief Lessons on Physics by Carlo Rovelli. Zahid now works as a postdoctoral researcher at Technical University of Munich (TUM).

Zahid reflects on his experience of undertaking a PhD as part of the CDT:

I believe that life is a journey from nowhere to nowhere. The pleasure of living is in the process itself, and destinations only milestones leading us to the next journey. On this path, we meet all kinds of people. While some settle down on the way, others continue to live nomadic academic lives. As a foreign student, I identify myself with migratory birds, who leave behind many relationships, friendships, cultural and sensory experiences of material and non-material things, seeking better learning and living conditions. In the quest for knowledge and professional opportunities, the continuous struggle to assimilate into a new environment provides us with great learning opportunities, which broaden our mental horizons and deepen the understanding of life indeed.

The last 4 years of my life at the University of Exeter have been full of happenings, professionally and personally. I met some wonderful people, on-campus and off-campus. Many interactions turned into enduring friendships. First of all, I got a great sense of freedom in working with my PhD supervisors Dr Yongde Xia and Prof Yanqiu Zhu, which helped me to grow as an independent researcher. Also, my supportive colleagues and friendly environment of Functional Materials Laboratory (Lab 08) made the overall PhD experience very joyful and productive.

The doctoral training program (CDT) gave me the confidence to think independently and make my own research decisions. During this time, I developed some fruitful collaborations, especially with Dr Asif Tahir (Penryn campus), Prof. Roland Fischer (TU Munich), Prof. Freek Kapteijn (TU Delft, NL) and Prof. Ovidiu Ersen (University of Strasbourg, France). The work I did in these collaborations, greatly contributed to shaping my PhD project.

Along with the PhD, the last 4 years have been the most important time of my life. I married my partner Anna-Maria and became a parent of our lovely daughter Selma as if a sailboat navigating without a compass saw the shore and anchored. Countless moments of joy, peace and contentment, as well as many sleepless nights of childcare, frustrating days, lockdown months of Covid-19 and moving back and forth from Exeter to Munich, all made this time substantial.

We wish Zahid the best of luck with his future.

Zahid has co-authored the following publications:

2021

2020

2019

2018

Selected outreach activities

Zahid has translated a book Seven Brief Lessons on Physics by Carlo Rovelli from English to Urdu. It has recently published by the Mashal Books, LahorePakistan.

Zahid has presented at the following conferences:

  • M. Z. Hussain, Y. Xia; Presentation: Bi-MOF derived nanocomposites_applications in photocatalysis, GWPore: Conference on Porous Materials for Energy, Environment and Healthcare Applications, U.K. February 2021. (2nd best presentation award) 
  • M. Z. Hussain, R. A. Fischer, Y. Zhu, Y. Xia; Poster: Making heterostructures with water: Role of temperature and water steam in MOF derived TiO2/CuOx/Cu/C nanocomposites, Euromof-20193rd International Conference on MOFs and Porous Polymers, Paris, France. October 2019.
  • M. Z. Hussain, Y. Zhu, Y. Xia; Presentation: MOF derived photocatalysts for high efficient solar-light-driven H2 evolution. MCEC 2019, Conference on Materials for Clean Energy, NPL, London, U.K.  April 2019.
  • M. Z. Hussain, R. A. Fischer, Y. Zhu, Y. Xia; Presentation: MOF derived bimetal oxide/carbon composites: Synthesis and photocatalytic applications, 6th International Conference on Multifunctional, Hybrid and Nanomaterials, Sitges, Spain, March 2019.
  • M. Z. Hussain, R. A. Fischer, Y. Zhu, Y. Xia; Poster: MOF derived TiO2/C nanocomposites for photocatalysis, ICS Winter School on Catalysis, Innovative Catalysis and Sustainability Scientific and Socio-Economic Aspects, Turin, Italy. January 2019.
  • M. Z. Hussain, Y. Zhu, Y. Xia; Poster: MOF derivatives for visible-light-driven photocatalytic applications, 41st Annual Meeting of the British Zeolite Association (BZA), Cumbria, Ambleside, U.K. July 2018.
  • M. Z. Hussain, Y. Zhu, Y. Xia; Poster: Black porous ZnO@C nanocomposites derived from MOF-5 for highly efficient photocatalytic application, RAMS-Recent Appointees in Materials Science, University of Exeter, U.K. September 2017.
  • M. Z. Hussain, Y. Zhu, Y. Xia; Poster: MOF-5 derived ZnO/C nanocomposites for adsorption and photodegradation of organic pollutants, NIM Conference on Nanostructured Functional Materials for Sustainable Energy Provision, Munich, Germany. July 2017.

New Publication: Time-domain imaging of curling modes in a confined magnetic vortex and a micromagnetic study exploring the role of spiral spin waves emitted by the core

Congratulations to David Osuna, whose paper, ‘Time-domain imaging of curling modes in a confined magnetic vortex and a micromagnetic study exploring the role of spiral spin waves emitted by the core’, was published this month in Physical Review B. David has recently finished his PhD in the CDT and is now a postdoctoral research fellow at University of Exeter, as part of the Electromagnetic and Acoustic Materials Group (EMAG).

David explains the paper’s topic:

“This was a very fruitful collaboration with Dr. Paul Keatley, finally published after about 3 years of hard work!

Generally speaking, we have modeled and ‘filmed’ oscillations of the atomic magnetic spins in microscopic magnets and related them to other dynamics revealed from simulations. Understanding this type of dynamics as a whole is key to design spintronic devices, that may be essential for processing information in quantum computers, for example.

Abstract

The curling spin wave modes of a ferromagnetic vortex confined to a microscale disk have been directly imaged in response to a microwave field excitation using time-resolved scanning Kerr microscopy. Micromagnetic simulations have been used to explore the interaction of gyrotropic vortex core dynamics with the curling modes observed in the region of circulating in-plane magnetization. Hybridization of the fundamental gyrotropic mode with the degenerate, lowest frequency, azimuthal modes has previously been reported to lead to their splitting and counterpropagating motion, as we observe in our spectra and measured images. The curling nature of the modes can be ascribed to asymmetry in the static and dynamic magnetization across the disk thickness, but here we also present evidence that spiral spin waves emitted by the core can influence the spatial character of higher frequency curling modes for which hybridization is permitted only with gyrotropic modes of the same sense of azimuthal motion. While it is challenging to identify if such modes are truly hybridized from the mode dispersion in a confined disk, our simulations reveal that spiral spin waves from the core may act as mediators of the interaction between the core dynamics and azimuthal modes, enhancing the spiral nature of the curling mode. At higher frequency, modes with radial character only do not exhibit marked curling, but instead show evidence of interaction with spin waves generated at the edge of the disk. The measured spatiotemporal character of the observed curling modes is accurately reproduced by our simulations, which reveal the emission of propagating short-wavelength spiral spin waves from both core and edge regions of the disk. Our simulations suggest that the propagating modes are not inconsequential, but may play a role in the dynamic overlap required for hybridization of modes of the core and in-plane magnetized regions. These results are of importance to the fields of magnonics and spintronics that aim to utilize spin wave emission from highly localized, nanoscale regions of nonuniform magnetization, and their subsequent interaction with modes that may be supported nearby.

Fig. Time sequence of a radial-azimuthal spin wave mode simulated and experimentally imaged in a 2 micrometres diameter, 40 nm thick Permalloy disc with an in-plane RF excitation field at 10.24 GHz. Timestep is approximately 24 ps.

New Publication: An in situ investigation of the thermal decomposition of metal-organic framework NH2-MIL-125 (Ti)

Zahid Hussain

Congratulations to Zahid Hussain for his new paper, ‘An in situ investigation of the thermal decomposition of metal-organic framework NH2-MIL-125 (Ti)’ , recently published in Microporous and Mesoporous Materials.

Zahid explains the paper’s findings:

Metal-organic frameworks (MOFs) are exceptionally porous and highly crystalline coordination polymers. Since the late 1990s, MOFs have been intensively investigated for a large variety of applications such as gas separation and storage, energy storage and conversion, batteries, fuel cells, optoelectronics, sensing, supercapacitors, drug delivery and catalysis. However, many key questions need to be answered to optimize the synthesis of these materials for industrial-scale applications. In this study, we present an in-situ investigation of thermal conversion of a titanium-based MOF, NH2-MIL-125(Ti) under an inert atmosphere. In situ thermal analysis of NH2-MIL-125(Ti) reveals the presence of 3 defined stages of thermal transformation in the following order: phase-pure, highly porous, and crystalline MOF → intermediate amorphous phase without accessible porosity → recrystallized porous phase. The three stages occur from room temperature till 300 °C, between 350 and 550 °C and above ∼550 °C respectively. The derived disc-like particles exhibit a 35% volume shrinkage compared to the pristine MOF precursor. Highly crystalline N and/or C self-doped TiO2 nanoparticles are homogeneously distributed in the porous carbon matrix. The original 3D tetragonal disc-like morphology of the NH2-MIL-125(Ti) remains preserved in derived N and/or C doped TiO2/C composites. This study will provide an in-depth understanding of the thermal conversion behaviour of MOFs to rationally select and design the derived composites for the relevant applications.

The crystalline structure of Ti-MOF, NH2-MIL-125(Ti) and mechanism of its thermal decomposition.

 

 

We would also like to congratulate Zahid on passing his viva, and wish him the best of luck for his future career.

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.

Ned Taylor passes his viva!

Ned Taylor

Congratulations to CDT student Ned Taylor, who has just finished his PhD. His thesis was titled ‘Ab Initio Exploration of Interface Structures and Their Properties’.

Ned published five papers during his time as part of the CDT and presented at national and international conferences. He was also involved with the Metabuddies scheme- an outreach scheme led by our PGRs, who visit local schools to engage their students in physics and engineering.

Ned looks back on the experience of undertaking his PhD:

It is finally over. I have written my thesis, had my viva, completed my corrections and have been awarded my doctorate. Yesterday I had a final trek up to the Uni as a PhD student to pick up a copy of my thesis that I had printed for prosperity. It is weird to think that it is all over now; below are some of thoughts on my time as a postgraduate researcher.

A PhD is a unique experience for everyone. For me, it was a wonderful time and, although sometimes stressful, it was always worth it. I have relished in the opportunity to conduct research and the freedom to choose my path of study. I have learnt more about the materials that surround us than I had ever expected. The work was demanding, but that was never an issue as the topics were always fascinating. It was amazing going to conferences and have people attend talks to listen to the research that I conducted. Writing scientific papers was often rather tedious, but the outcome was definitely worth it and really helped in the process of writing my thesis.

I have learnt a lot throughout my PhD. In addition to the science, the courses offered by the CDT were, overall, very rewarding and useful. I learnt how to present, how to understand and communicate with others in a team, how to manage projects, how to put myself forward and highlight my skills. I feel that these skills will be vital for progressing beyond the PhD.

The community of PhD students in the CDT offered the chance to forge good friendships. Going on this journey with other PhD students helped me to relax and enjoy the experience. I am also extremely grateful for the support and guidance that my supervisors, Steve Hepplestone and Eros Mariani, have given me throughout the past four years.

As became a theme in the Hepplestone research group near the end of my PhD (before multiple lockdowns, that is), I shall summarise this chapter of my life with a haiku:

DFT was fun
Lots of time spent fighting tech
PhD is done

With my PhD complete, I am now transitioning over into the field of computer science. I have just started a postdoctoral research fellow position at University of Exeter, looking at ways of automating transport models for use in reducing the carbon impact of traffic systems.

We wish Ned all the best with his new role.

Below is a list of Ned’s publications, and conferences he has presented at:

Ned has co-authored the following publications:

2020

2019

2017

Ned has presented at the following conferences:

 

Training and other events: January 2021 to March 2021

Please find below a table of all upcoming XM² training and other events from January 2021 to March 2021, as far as planning currently allows and subject to change.

PGRs, please highlight any XM²-training related absence times to your supervisors. In regards to annual leave or other absence time planning: all confirmed events have been sent to the PGRs via an Outlook calendar invitation, but please ensure to check the CDT in Metamaterials Outlook calendar and to liaise with your supervisors and the CDT in Metamaterials office (metamaterials@exeter.ac.uk) for approval BEFORE you make any bookings, as there might be a few more events coming up that are yet to be confirmed.

Supervisors, please be mindful of the XM² events when setting expectations on research deliverables with the PGRs.

January
04.01.21 CDT Group Meetings All PGRs 16:30-17:30 via Teams
12.01.21 Write About Science (Part 1) 1st years 09:00-13:00 via Zoom
13.01.21 Write About Science (Part 2) 1st years 09:00-13:00 via Zoom
22.01.21 ALL: Metamaterials Colloquium, Prof. Roland A. Fischer. Technical University of Munich, ‘Integration of Metal-Organic Frameworks to Devices: (SUR)MOF-Derived Electrocatalysts for Water-Splitting and Fuel Cell Applications’ All PGRs 12:30-13:30 via Zoom
27.01.21 Wave Theory 1st years 09:30-10:30 via Zoom
28.01.21 OPTIONAL: SPARK (Entrepreneurial Skills Course) 4th years, 3rd years, 5th years 09:30-10:30 via Zoom
February
01.02.21 CDT Groups All PGRs 16:30-17:30 via Teams
03.02.21 Wave Theory 1st years 09:30-10:30 via Zoom
10.02.21 Wave Theory 1st years 09:30-10:30 via Zoom
12.02.21 Metamaterials Colloquium: Prof Marc Holderied, University of Bristol, ‘Acoustic metamaterials give moths stealth camouflage against bat biosonar’ All PGRs 12:30-13:30 via Zoom
16.02.21 Month 6 Assessment Briefing 1st years 10:00-11:00 via Microsoft Teams
17.02.21 and 18.02.21 Leadership Training 3rd years 09:30-16:30 (on both days) via Zoom
19.02.21 Beyond a PhD: Dr Jade Phillips, Research and Development Ingredient Specialist at Jacobs Douwe Egberts All PGRs 12:30-13:30 via Zoom
24.02.21 Wave Theory 1st years 09:30-10:30 via Zoom
March
03.03.21 Wave Theory 1st years 09:30-10:30 via Zoom
10.03.21 Wave Theory 1st years 09:30-10:30 via Zoom
17.03.21 Wave Theory 1st years 09:30-10:30 via Zoom
17.03.21 Presentation Skills 1st years 14:00-15:00 via Teams (sign-up required)
24.03.21 Wave Theory 1st years 09:30-10:30 via Zoom
25.03.21 Interview Skills 4th years 09:00-17:00 via Zoom
31.03.21 Wave Theory 1st years 09:30-10:30 via Zoom

After six months, (e.g. after the Month 6 project is complete), first year PGRs can undertake teaching and demonstrating, provided that they complete LTHE online training first. The course is self-paced so you can take it whenever you like but please note it is mandatory and you will not be able to undertake teaching and demonstrating until you have completed it.

 

 

New Publication: Tunable pseudo-magnetic fields for polaritons in strained metasurfaces

Congratulations to final year PhD student Charlie-Ray Mann whose theory paper, entitled ‘Tunable pseudo-magnetic fields for polaritons in strained metasurfaces’, has been published in the prestigious journal Nature Photonics.

The work has also been featured on the University of Exeter’s news website.

Charlie-Ray Mann, the lead scientist and author of the study, explains:

Charlie-Ray Mann- lead scientist and author of the paper published in Nature Photonics

The interaction between charged particles and magnetic fields gives rise to some of the most fascinating phenomena in physics, ranging from the beautiful Aurora Borealis to the famous quantum-Hall effect. Unfortunately, because photons do not have an electric charge they are inert to real magnetic fields as they do not experience a Lorentz force.

Taking inspiration from graphene physics, we have shown that you can generate `artificial’ magnetic fields for light by distorting honeycomb metasurfaces in a specific way. These distortions generate a ‘synthetic’ Lorentz force which can deflect the surface polaritons into effective cyclotron orbits, and for larger distortions one can also observe Landau quantization of the polaritons — phenomena once thought to be exclusive to charged particles.

However, the main drawback with this approach is that to change the artificial magnetic field one is usually required to modify the distortion in the lattice. This is extremely challenging, if not impossible to do with photonic structures, hindering our ability to tune the artificial magnetic field after the structure has been fabricated — that is, the artificial magnetic fields are usually fixed by design.

In this theoretical work we have proposed an alternative mechanism to tune the artificial magnetic fields, which requires no change to the metasurface distortion. By exploiting the hybrid light-matter character of the surface polaritons, we show that one can tune the artificial magnetic field by modifying the real electromagnetic environment surrounding the metasurface.

Specifically, we’ve shown that by embedding the metasurface inside a photonic cavity or waveguide, one can tune the artificial magnetic field by modifying a single external parameter: the cavity width. In fact, we’ve even demonstrated that you can switch off the artificial magnetic entirely at a critical cavity width, without having to remove the distortion in the metasurface — something that is impossible to do in graphene or any system that emulates graphene.

Using this new mechanism you can bend the trajectory of the polaritons using a tunable Lorentz-like force that can be switched on/off, and you can drastically reconfigure the polariton Landau level spectrum by simply changing the cavity width.

Earlier this year, Charlie-Ray Mann was awarded a £5,000 prize from the Rank Prize Funds 2020.