About us

Vopson research is a blog associated with Dr Vopson's Physics research activities at the University of Portsmouth, School of Mathematics and Physics, Faculty of Technology.

First Synchrotron experiment

ON 3-6 July 2018 Dr Vopson attended the Synchrotron facility, Diamond Light Source, in Oxfordshire together with his team, Mr Belusky and Dr Namvar.

Image - Dr Vopson on Beam I11 changing a sample.

This is part of a DLS grant won by Dr Vopson to study anti-ferroelectric materials using synchrotron measurements. After a slow start, the experiment appears to have been a mega success. Dr Vopson is still analysing the data, but the preliminary results are extremely encouraging. Without disclosing more info now, we will shortly publish our results and the article will be linked on this blog.

Dr Vopson elected a Fellow of IOP

In May 2018 Dr Melvin Vopson has been elected Fellow of the Institute of Physics.

A new technique to study ferroelectrics developed at University of Portsmouth

A new technique to study ferroelectrics developed by Dr Vopson at the University of Portsmouth has just been published. This is a very powerful new experimental method that could have a significant impact on the solid state ferroelectrics community as it provides the means to extract experimentally unique information such as intrinsic interaction and switching field distribution in ferroelectric solids.   

A new method to study ferroelectrics using the remanent Henkel plots

Published 30 April 2018 • © 2018 IOP Publishing Ltd
, ,

Full article link: http://iopscience.iop.org/article/10.1088/1361-6463/aabe16 

Liam Soomary wins the 2018 AMS award for the Best Materials Physics Project

Congratulations to Liam Soomary for winning the 2018 Applied Materials Society award for the Best Materials Physics Project, for his work on Surface Characterization on SiC. Liam's work was a combination of research undertaken in Poland within an ERASMUS exchange visit and at the University of Portsmouth under the supervision of Dr Krupski.




Image: Liam Soomary (left) receiving the award from Melvin Vopson (right), during the Level 6 project posters conference in March 2018. 

PhD bursary in Physics - University of Portsmouth


Development of multicaloric technologies for advancement of efficient cooling systems

Applications are invited for a highly interdisciplinary PhD studentship to research the design, development and testing of a multicaloric instrument, as well as to investigate multiferroic materials suitable for multicaloric solid state cooling. The three years post is available from 01 Oct 2018 and the successful candidate will receive a full University PhD bursary of £14,777 per annum.

How to apply:
We welcome applications from highly motivated prospective students who are committed to develop outstanding research outcomes. You can apply online at http://www.port.ac.uk/applyonline. Please quote project code MPHY4310518 in your application form.

A link to the online application form and comprehensive guidance notes can be found at www.port.ac.uk/pgapply

Informal enquiries are encouraged and can be made to Dr Melvin Vopson at melvin.vopson@port.ac.uk (02392 842246) or Prof. Mark Gaterell at mark.gaterell@port.ac.uk (02392 842943)

Applied Materials Society - 2018 Best Materials Physics Award


In May 2018, the Applied Materials Society will award one of the Physics level 6 students at the University of Portsmouth, the:

2018 Best Materials Physics Project Prize

The Award is in recognition of the most interesting and detailed research project in Condensed Matter Physics at level 6 undertaken during the 2017 - 2018 academic year. The winning research could be either theoretical or experimental, but the topic is restricted to Materials Science, Condensed Matter and Solid State Physics research. The AMS will announce the winner of this award at the Physics graduation poster conference in May 2018.

Successful Diamond Light Source proposal

Our Beam-line proposal at Diamond Light Source:

In-situ synchrotron studies of anti-ferroelectric materials for digital data storage

scheduled in the allocation period 23 from Apr 2018 - Oct 2018, has been awarded  6 shifts on I11: High Resolution Powder Diffraction.

EPSRC:Research Grant Success

Our EPSRC proposal:

Anti-ferroelectric materials for non-volatile memory applications

 has just been awarded. This grant will facilitate Dr Vopson's travel for five weeks to three overseas institutions, in two countries, in order to perform and receive training on specialized experiments for anti-ferroelectric materials. The partner institutions are: Western Digital, a multibillion $ data storage company based in California, Iowa State University and the National Institute of Materials Physics (NIMP), Bucharest.

Plasma sputtering system upgrade

We are pleased with the completion of the first part of our LabLine Plasma Sputtering upgrade. The system has been improved by adding a second mass flow controller (MFC) to allow the Oxygen / Argonne reactive plasma sputtering of oxide dielectric materials. The second part of the upgrade is to connect the Oxygen gas bottle to the MFC.
The ECLIPSE software has been already upgraded. This is an excellent capability / addition that will support at least two L6 project students this year and one PhD student research.

Our first research paper on KJL LabLine Plasma Sputtering system published

Physica B: Condensed Matter Physica B: Condensed Matter, Volume 525, 15 November 2017, Pages 12-15

Development of flexible Ni80Fe20 magnetic nano-thin films 

 M.M. Vopson, J. Naylor, T. Saengow, E.G. Rogers, S. Lepadatu, Y.K. Fetisov

Flexible magnetic Ni80Fe20 thin films with excellent adhesion, mechanical and magnetic properties have been fabricated using magnetron plasma deposition. We demonstrate that flexible Ni80Fe20 thin films maintain their non-flexible magnetic properties when the films are over 60 nm thick. However, when their thickness is reduced, the flexible thin films display significant increase in their magnetic coercive field compared to identical films coated on a solid Silicon substrate. For a 15 nm flexible Ni80Fe20 film coated onto 110 µm Polyvinylidene fluoride polymer substrate, we achieved a remarkable 355% increase in the magnetic coercive field relative to the same film deposited onto a Si substrate. Experimental evidence, backed by micro-magnetic modelling, indicates that the increase in the coercive fields is related to the larger roughness texture of the flexible substrates. This effect essentially transforms soft Ni80Fe20 permalloy thin films into medium/hard magnetic films allowing not only mechanical flexibility of the structure, but also fine tuning of their magnetic properties.

Get full text here: https://authors.elsevier.com/a/1VgqF3HWvdxey4

A big welcome to our new PhD students in AML

Two new PhD students have been recruited to work in the Applied Materials Laboratory under Dr Vopson's supervision. Mr Michal Belusky will undertake a full time research project investigating "Deposition of flexible thin films via magnetron plasma sputtering". Mr Andrew Nomuoja will start his part-time PhD on a project involving theoretical and experimental studies of polarization dynamics in ferroelectric and anti-ferroelectric materials. We wish a warm welcome to both new members and best of luck with their research projects.

A memory effect in anti-ferroelectric materials discovered

Initial studies of anti-ferroelectric materials in the Applied Materials Laboratory at the University of Portsmouth indicate that these polar dielectrics can store digital information. The experimental results are very encouraging and an article is in preparation. Dr Vopson and Prof. Tan from Iowa State University, are currently working on the proposal of a novel anti-ferroelectric random access memory chip (AFRAM) that will compete with traditional ferroelectric random access memory (FRAM) to deliver twice the memory storage capacity in the same volume.

New Research published on Multicaloric Effect

The induced magnetic and electric fields’ paradox leading to multicaloric effects in multiferroics
M.M. Vopson 
Solid StateCommunications231-232(2016)14–16 

A b s t r a c t
Magneto-electric effect in multiferroics implies that an applied magnetic field induces an electric polarization change in a multiferroic solid and viceversa, an applied electric field modifies its magnetization. The magneto-electric effect is a powerful feature of multiferroics and has attracted huge interest due to potential technological applications.One such possible application is the multicaloric effect in multiferroics. However, a closer examination of this effect and its derivation leads to a paradox, in which the predicted changes in one of the order phase at a constant applied field are due to the excitation by the same field. Here this apparent paradox is first explained in detail and then solved. Understanding how electric and magnetic fields can be induced in multiferroic materials is an essential tool enabling their theoretical modeling as well as facilitating the introduction of future applications.
& 2016Elsevier Ltd. All rights reserved.
Full text: http://dx.doi.org/10.1016/j.ssc.2016.01.021


Applied Materials nano-Thin Films Laboratory becomes fully functional

The nano-thin films teaching laboratory within the Applied Materials Laboratory at the University of Portsmouth becomes fully operational. This is a major teaching facility that will deliver at least 2-3 student projects per year, as well as PhD and MSc/Mres research work.


Thin films deposition via plasma magnetron sputtering



LabLine Kurt J. Lesker Plasma Sputtering System
5 magnetron targets, 4 DC and one RF
One magnetron target for magnetic materials
4 substrates holder with automated indexing for
deposition of individual or multi-layers
Substrates heater up to 450 C
2 Quartz thickness rate monitors (resolution 0.1 A/s)

Applications of multiferroic materials review published

Fundamentals of Multiferroic Materials and Their Possible Applications
Melvin M. Vopson (2015): Fundamentals of Multiferroic Materials and Their Possible Applications, Critical
Reviews in Solid State and Materials Sciences, DOI: 10.1080/10408436.2014.992584

This article is the basis of the Introduction to Multiferroic materials and their Application teaching Unit offered by Dr Vopson to University of Portsmouth Applied Physics students at Level 6 / year 3. Most of the teaching material is now published in this major review article.  

Abstract
Materials science is recognized as one of the main factors driving development and economic growth. Since the silicon industrial revolution of the 1950s, research and developments in materials and solid state science have radically impacted and transformed our society by enabling the emergence of the computer technologies, wireless communications, Internet, digital data storage, and widespread consumer electronics. Today’s emergent topics in solid state physics, such as nano-materials, graphene and carbon nano-tubes, smart and advanced functional materials, spintronic materials, bio-materials, and multiferroic materials, promise to deliver a new wave of technological advances and economic impact, comparable to the silicon industrial revolution of the 1950s. The surge of interest in multiferroic materials over the past 15 years has been driven by their fascinating physical properties and huge potential for technological applications. This article addresses some of the undamental aspects of solid-state multiferroic materials, followed by the detailed presentation of the latest and most interesting proposed applications of these multifunctional solid-state compounds. The applications presented here are critically discussed in the context of the state-of-the-art and current scientific challenges. They are highly interdisciplinary covering a wide range of topics and technologies including sensors, microwave devices, energy harvesting, photo-voltaic technologies, solid-state refrigeration, data storage recording technologies, and random access multi-state memories. According to their potential and expected impact, it is estimated that multiferroic technologies could soon reach multibillion US dollar market value.
To link to this article: http://dx.doi.org/10.1080/10408436.2014.992584

Novel magnetic data storage beyond super-paramagnetic limit

Multiferroic composites for magnetic data storage beyond the super-paramagnetic limit

Researchers in the Applied Materials Laboratory at the University of Portsmouth led by Dr Vopson, in collaboration with colleagues from Institute Jozef Stefan - Slovenia, published a novel concept of multiferroic magnetic data storage that functions beyond the super-paramagnetic limit. 
JOURNAL OF APPLIED PHYSICS 116, 113910 (2014)

Abstract
Ultra high-density magnetic data storage requires magnetic grains of <5 nm diameters. Thermal stability of such small magnetic grain demands materials with very large magneto-crystalline anisotropy, which makes data write process almost impossible, even when Heat Assisted Magnetic Recording (HAMR) technology is deployed. Here, we propose an alternative method of strengthening the thermal stability of the magnetic grains via elasto-mechanical coupling between the magnetic data storage layer and a piezo-ferroelectric substrate. Using Stoner-Wohlfarth single domain model, we show that the correct tuning of this coupling can increase the effective magnetocrystalline anisotropy of the magnetic grains making them stable beyond the super-paramagnetic limit. However, the effective magnetic anisotropy can also be lowered or even switched off during the write process by simply altering the applied voltage to the substrate. Based on these effects, we propose two magnetic data storage protocols, one of which could potentially replace HAMR technology,
with both schemes promising unprecedented increases in the data storage areal density beyond the super-paramagnetic size limit. VC 2014 AIP Publishing LLC.

[http://dx.doi.org/10.1063/1.4896129]

Applied Materials Laboratory (AML) Blog launch



The lead scientist of the Applied Materials Laboratory (AML) at the University of Portsmouth has officially launched the AML Blog on the 19th of March 2014. 

The Blog will offer regular updates on the core teaching and research activities within this laboratory. 
We welcome contributors and comments, especially from our students. To get access as contributor please contact Dr Vopson. 
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