Research
Bálint NáfrádiSBLaboratory of Physics of Complex Matter (LPMC)EPFL//ICMP/LPMCPH D2 484 (Bâtiment PH)Station 3CH-1015 LausanneSwitzerlandE-mail:nafradi at yahoo dot comweb:http://nafradi.eu/research interesteducation
publicationslast updated: 22.01.2014
Interest
I am an experimental physicist with a core of expertise in solid state physics. My interest lies in multidisciplinary, fundamental research but with a special emphasize on possible applications testified by myscientific papers and patents, respectively. I believe to answer pertinent questions in these research fields the use ofhigh-resolution spectroscopicmethods are the key.
Fields I'm currently working on:
- Electron Spin Based Information TechnologiesOne of the big challenges of our society is in information and communication technologies (IT). In our IT-dependent society raw data is produced at an enormous rate: their volume roughly doubles every 40 months while the amount of transferred data increases even faster, it doubles in every 20 months. On an absolute scale, in 2015 every citizen of the developed world produced digital data that would need 900 CDs for storage, the information exchange through two-way telecommunication networks reached the volume of
700 newspapers per person per day. The main drivers of this Digital Revolution are novel information and communication technologies, which are profoundly changing all aspects of our everyday life ranging from research, economy, sport, healthcare to the documentation of cultural heritage. In order to sustain this incredible growth and to satisfy the needs of our information-hungry society we have to address three major technological challenges:
- the data should be processed rapidly,
- the data should be transferred swiftly, and
- the data should be stored.
- Moreover, for ecological sustainability it should be done in an energy efficient way.
My research targets all these chalenges raised by the ongoing digital revolution.
- My research on electron spin basedquantum bitsputs special emphasis to reach room temperature operation for quantum computers.I believe this is a prerequisite for a truly transformational technology. This is described in detail in my recent Review Paper invited by Advanced Functional Materials.
- Classical information transfer based on electron spins.
- Classical information storage based on electron spins.
- Topologically protected statesfor possible quantum bits.
Radiation Detection and Harvesting
Apart from research I also take an active role in education of highly motivated and talented young scientists by preparing them to science competitions and graduate student workshops.
I also take an active role in the popularization of science for general audience. I'm an editor ofWikipeidawhere I mostly contribute toPhysicsarticles in English and in Hungarian.
In order to disseminate my work to broad audience I regularly contribute no news feeds and science and technology related blogs.
Case studies:
Spectrometer Development
I have developed a one-of-the-kind ESR spectrometer working in the exceptionally broad frequency range of 1-420 GHz frequency range in the corresponding 0-16 T magnetic field range in contrast to conventional X-band ESR spectrometers operated at 9.6 GHz (0.34 T). Moreover, experiments can be performed in a multi-extreme environment in 1.3-400 K temperature range and up to 2.0 GPa hydrostatic pressure. Due to my innovative technical developments the high-frequency ESR spectrometer, even after 8 years of operation, still holds several records is terms of sensitivity, resolution and pressure. And it is the sate-of-the art. This work is continuously ongoing by extending pulsed operation and in situ optical excitations which are instrumental for my current research.
Details can be foundhereandhere.
Spin Based Quantum Bit
A general shortcomings of quantum computing schemes are the cryogenic temperature range where they are operational and the limited integrability to the existing CMOS based computing architectures. These factors significantly hinder broad range applicability. I have studied the spin dynamics of a new class of conducting carbon nanospheres by ESR. I have demonstrated their potential as spin-based Qbits for room temperature operation with feasible integration to CMOS architectures.
Details can be foundhere.
Our work received significant online attention, over 4000 downloads in the first week which made it to the top 3 percentile of all nature papers. Moreover, several news science and technology blog picked up the news like
Word Economic Forum
Science Alert
Bio Portfolio
Real Clear Science
lifehacker
Controlled Environments
The Inquirer
Phys.org
Australian Science
The Conversation
abc news
nanowerk
Spin Based Classical Information Storage
The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Based on multi frequency ESR studies lead by me a new mechanism for optical control of magnetic ground state of photoresistors have been discovered. We showed that this mechanism can form a basis of a new magneto-optical data storage technology. My ongoing work on this field targets optically tunable ultrafast satellite microwave telecommunication.
Spin Based Classical Information Transmission
Spintronics the information transferred by the electron spins encoded by the spin projection relative to a quantizing axis. It is a classical process where the limiting parameter the spin lattice relaxation time of electrons (T1) which limits bot the time-frame while the information is maintained and the distance where the information can be transferred. A promising system for this processes is graphene. However, until recently the intrinsicT1of graphene was wrongly estimated to be in the range of 1-2 ns. My work has shown that the intrinsicT1of graphene exceed 100 ns, however environmental effects and particular O2absorption reduces it to the few-ns range.
Details can be foundhere,hereandhere.
Biology Inspired Interdisciplinary Studies
For efficient contrast agents for Magnetic Resonance Imaging (MRI) there are two essential requirements. Firstly they must be safe to use. Secondly the electronic magnetic dipole-field should be maximal at the neighbouring water protons. A new MRI contrast agent Gd3N@C80showed unprecedented 1000 fold increase of MRI contrast relative to commonly used Gd(III) chelates and exceptional stability in vivo. My work based on multi-frequency ESR spectroscopy revealed that the interplay of ferromagnetic correlations and molecular rotation of Gd3N results in the remarkable MRI characteristics. My study also demonstrated the power of multi-frequency ESR in study of molecular dynamics by following the rotation of Gd3N@C80molecules.
Details can be foundhere
The spin lattice relaxation time (T1) of organic radicals is one of the key parameters in Dynamic nuclear polarization (DNP). The other is the Larmor frequency of the electron spins at DNP magnetic field. I have recently developed a longitudinal detection method to directly measureT1and Larmor frequency of organic radicals in an unprecedentedly broad magnetic field range of 0-16 T directly relevant for high-frequency DNP.
Optical and photocurrent spectroscopy
I'm actively involved in the fundamental research for understanding the governing principles of photo electric activity of metalorganic halide perovskites. My work based on various optical spectroscopic techniques covering a broad range of wavelength (IR to γ-rays) resulted is several technologically relevant proposals ranging from ultrasensitive photo detection with single-photon efficiency at room temperature relevant in quantum-optical information transfer, to waste radiation harvesting in fission and fusion power plants, or space based radiation detection and energy harvesting.
More details can be foundhere,here,here,here,here,
International Business Times
(20min delay)