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.
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.
& 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)
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
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]
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.
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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