3^rd International Conference on Magnetism and Magnetic Materials October 22-23, 2018 Rome, Italy

Chair

Fedor Pudonin

P.N. Lebedev Physical Institute of RAS, Russia

Co-Chair

Karine Chesnel

Brigham Young University, USA

Session Introduction

Shavkat U Yuldashev

Dongguk University, South Korea

Title: Critical behavior of GaMnAs diluted magnetic semiconductors near the Curie temperature

Biography:

Shavkat U Yuldashev has completed his PhD in the year 1983 from A.F. Ioffe Institute, Saint-Petersburg. He is the Professor at the Department of Physics of Dongguk University, Seoul, South Korea. He has published more than 175 papers in reputed journals. His expertise is in diluted magnetic semiconductors and spintronics.

Abstract:

GaMnAs have been studied intensely over the last few decades and have become a model system for diluted ferromagnetic semiconductors. At present, it is accepted that the Curie temperature of GaMnAs with metallic type of the conductivity coincides well with the maximum of the temperature derivative of the resistivity dρ/dT, similar to the ferromagnetic metals like Ni and Fe, whereas, for samples with low concentration of free carriers, the T_C coincides with the resistivity maximum. The critical behavior of GaMnAs near the Curie temperature was experimentally studied by using the temperature dependencies of the resistivity, the specific heat, and the magnetization of GaMnAs. It is shown that the determination of T_C from the maximum of the temperature derivative of the resistivity is valid only for the samples with a high concentration of free carriers. For the samples with low concentration of free carriers, the T_C coincides with the resistivity maximum. The magnetic specific heat for T > T_C demonstrates the crossover from the one dimensional to the three dimensional critical behavior when temperature become closer to the Curie temperature. This is explained by the existence of Mn-Mn dimers oriented along one direction at the beginning of the formation of the ferromagnetic phase on the paramagnetic side of the phase transition.

Vladimir V Matveev

Saint Petersburg State University, Russia

Title: Potential of the NMR-in-magnetics technique in the study of local structure of various magnetic materials

Biography:

Vladimir V Matveev has completed his PhD from Semenov Institute of Chemical Physics of USSR Academy of Sciences. He is a Senior Researcher of Department of Nuclear-Physics Investigation Techniques of Saint Petersburg State University, Russia. He has published more than 25 papers in reputed journals and made a lot of reports/lectures at international conferences.

Abstract:

The lecture is devoted to nuclear magnetic resonance (NMR) in the magnetically ordered state of matter. The technique is also known as NMR in magnetics or spin echo, or FNR. This method possesses a considerable potential for effective investigation and testing of various magnetic materials, especially in the nanocrystalline and/or in nanocomposite state. In the first part of the lecture an introduction is done to basic physics of pulse NMR in magnetics together with a brief description of the method development since its appearance, about 60 years ago. The method was successfully applied to a lot of magnetics such as metallic cobalt and cobalt-containing materials, including films, multilayers and nanoparticles; various ferro- and ferrimagnetic compounds, Heusler alloys, intrinsically inhomogeneous perovskite-like CMR manganites etc. A number of works of different years demonstrate that NMR technique was the useful addition to well known diagnostic methods of magnetic materials and allowed one to get unique information. In the second part of the lecture we review applications of the technique to some novel magnetic structures/materials during the last few decades. In particular, we describe a determination of the core-shell structure of bimetallic FeCo nanoparticles, an observation of ferromagnetic clusters in spin-glass manganites far above Curie temperature, molecular magnets i.e., array of molecular complexes with several 3d-metal ions, Mn-doped magnetic semiconductors, and a detection of zero-field ¹³C NMR signal in so-called magnetic carbon i.e., in carbon-based magnetic materials free from metallic elements. 

Liubov Lukina

KU Leuven, Belgium

Title: A step towards magnetic separation of rare earth ions

Biography:

Liubov Lukina obtained her Engineer diploma from the National Mineral Resources University in Saint Petersburg, Russia in 2015. Subsequently, she completed the Master program in Chemical Engineering in Lappeenranta University of Technology, Finland in 2016. Since her Master thesis work concerned separation of rare earth metals, she decided to pursue researching this direction. Currently, she is working on her Doctoral thesis on the border of Chemistry, Physics and Engineering in University of KU Leuven in Belgium. She hopes that her work will help developing green methods for rare earth metal recycling from electronic and mining waste.

Abstract:

Rare earth metals are critical elements for many high-tech applications, e.g. electric vehicles, wind power generators and electronics. Due to the scarcity of rare earth metal supplies in Europe, it is clear that new efficient, environmentally friendly and cheap methods for separating rare earth metals from electronic and mining waste are needed. Currently used solvent extraction process is time-consuming and not efficient. In this context, magnetic separation of rare earth ions looks promising. Magnetic separation is a well-established method used in ore processing, food industry, biomedical diagnostic etc. The method of magnetic separation is based on the fact that REM have different magnetic susceptibilities: some of the rare earth ions are strongly paramagnetic (Dy³⁺, Ho³⁺), which means that they move towards the magnet; the other rare earth ions are diamagnetic (Sc³⁺, Y³⁺, Lu³⁺), hence they will move away from the magnet. Particles, cells and molecules easily undergo separation in a magnetic field. However, magnetic separation of ions has not been reported since 1950s. In this work, magnetomigration of rare earth ions was investigated using a separation device. The separation device featured a 2.5 ml³ cell where rare earth solution was enclosed and circulated due to natural convection. Magnetic field was applied to the device using a magnetic yoke setup. Enrichment of paramagnetic Dy³⁺ ions in the paramagnetic fraction was achieved. Simulation of the experimental system in Comsol 5.2 is allowed to verify the observed fluid flow and temperature patterns. Magnetomigration is the first step to magnetic separation of rare earth ions.

K N Guruprasad

Shri Vaishnav Institute of Science, India

Title: Enhancement of germination in maize (Zea mays variety: Ganga safed) by magnetic field signal transduction

Biography:

K N Guruprasad is a Director of Shri Vaishnav Institute of Science, SVVV, Indore, Madhya Pradesh, India. He has worked in the area of photobiology and magneto-biology for over 30 years and has published over 85 research papers in journals of international repute. His work on improvement of crop yields by magnetic field treatment is gaining importance in the field of agriculture as a non-invasive physical method that can enhance the performance of crop plants.

Abstract:

Maize (Zea mays variety: Ganga safed) seeds treated with static magnetic field (SMF) strength of 200 mT showed enhanced germination and seedling vigor. This stimulation leads to better growth of plants and improves the yield of the plant under field conditions. The initial biochemical events soon after treatment of seeds with SMF have been analyzed. SMF treatment induces production of reactive oxygen species (ROS) and nitric oxide (NO) besides enhancing the activity of amylase enzyme. Inhibitors of NO like sodium tungstate (ST) and N-nitro-L arginine methyl ester hydrochloride (L-NAME) inhibit the promotion of seedling growth by SMF. Similarly diphenyleneiodonium (DPI), an inhibitor of NADPH-oxidase enzyme which generates ROS, also inhibits SMF promoted seedling growth. On the contrary, sodium nitroprusside (SNP), a donor of NO, promotes SMF stimulated growth. The biochemical signal transduction of SMF for the promotion of germination and seedling growth is through the production of ROS and NO. ROS can directly degrade the stored food materials like starch in the seeds. NO is a known germination stimulator and an activator of amylase enzyme. The receptors of the magnetic field in the seeds which stimulate the production of these radicals are yet to be ascertained.

Elena V Ezerskaya

VN Karazin Kharkiv National University, Ukraine

Title: Low temperature properties of low-dimensional exactly solvable spin models with impurities

Biography:

Elena Ezerskaya has completed her PhD in the year 1985 from VN Karazin Kharkiv National University. She is Associate Professor at the Theoretical Physics Department of VN Karazin Kharkiv National University. She has published more than 30 papers in reputed journals. She is experienced university teacher and researcher in field of Theoretical Physics for more the 30 years, supervisor of MS and PhD students.

Abstract:

This work is devoted to the theoretical study of quantum stationary states and thermodynamics of some exactly solvable quantum models based on spin-1/2 XX-chain. Low-dimensional spin models occupy special place in quantum theory of magnetism. Some of these systems may have exact analytical solutions. In our study we consider the spin chains with defects: infinite XX-chain with impurity fragment, finite linear XX-chain with an additional ZZ (Ising) bond, two finite XX-chains, connected through an additional ZZ spin, finite spin-1/2 XX-chain closed by one zz (Ising) bond and open ends XX-chain with two zz-impurities at the both ends. For infinitive spin-1/2 XX-chain with impurity fragment in longitudinal magnetic field the exact energy spectrum is found. This spectrum consists of the energy band, set of discrete levels, and may contain from one up to four bound states localized on the boundaries of impurity fragment and main chain. We studied the critical behavior of local static thermodynamic characteristics and time dependence of dynamical longitudinal correlation functions at different temperatures. For finite XX-chain with Ising defects the localized levels near the impurity spin may exist in the spectrum. The conditions for their appearance were found. The field and temperature dependences of some thermodynamic characteristics of the models are studied. It is shown that the localized levels may effect noticeably on local thermodynamic characteristics.

Yasuhiro H Matsuda

University of Tokyo, Japan

Title: Condensed matter physics in 100 – 1000 T ultrahigh magnetic fields

Biography:

Yasuhiro H Matsuda completed his PhD in the year 1996 from Tohoku University. He is the Associate Professor of The Institute for Solid State Physics, The University of Tokyo. He has published more than 100 papers in reputed journals. He is expertise in high-magnetic-field science and condensed matter. His discoveries of novel field-induced phases shed new light on condensed matter physics.

Abstract:

Ultrahigh magnetic field in the range of 100-1000 T opens new research fields in condensed matter physics. The spin Zeeman energy of a free electron reaches 1350 K (0.116 eV) at 1000 T that is large enough to change electronic as well as structural properties of matter. Various kinds of phase transitions can be induced by such ultrahigh magnetic fields and the novel high-field phase is regarded as a kind of new material. Destructive ways are only available for generation of the 100-1000 T fields and thus the time duration of the pulsed-fields is in the microsecond range, which requires us to develop special measurement techniques to overcome this severe condition. For magnetic field generation, the single-turn coli and the electromagnetic flux compression techniques have long been developed in our institute (the Institute for Solid State Physics (ISSP)) and can generate up to 300 and 1000 T, respectively. Various kinds on intriguing phenomena such as the structural phase transition of solid oxygen, magnetic phase transitions in low dimensional magnets, novel spin-state transitions in cobalt-oxides, and the insulator-metal transition in a Kondo material are recently discovered in ultrahigh magnetic fields. Such recent physical achievements as well as developments of magnet technology are presented. 

Zhe Li

Cardiff University, UK

Title: Toward addressing the stability challenge of solution processed organic solar cells

Biography:

Zhe Li has completed his PhD in early 2012 from University of Cambridge and Postdoctoral studies from Imperial College of London in 2014. Later on he joined Swansea University as a Research Fellow (2014-2016) and Senior Research Fellow (2016-2017). He is now a Lecturer in Energy Materials at School of Engineering, Cardiff University. He has published more than 30 papers in reputed journals and holder of one industrial patent.

Abstract:

As a next generation photovoltaic (PV) technology, solution processed organic solar cells have undergone significant improvements in their performance, now achieving the threshold for commercial viability. However, their environmental stability has been widely recognized as a major bottleneck for their commercialization. Various environmental factors including light, heat, oxygen and humidity, are known to cause rapid degradation of their performance, with the majority of their degradation mechanisms still remaining widely unclear. Such limitation has imposed further challenges in device encapsulation, which results in significant process limitations, higher costs and only partially effective process solutions. Organic solar cells are typically based upon solution processed conjugated donor polymers with the soluble fullerene derivative PCBM or its larger analogue PC₇₀BM. However, fullerenes are known to be expensive to fabricate and purify, and their weak optical absorption in the visible/near-infrared region and narrow range of available energy levels have limited further efficiency optimisation of organic solar cells. Recently, their highly sensitive nature to light and oxygen, as well as high tendency to nucleate and crystallize have been identified as primary degradation pathways of organic solar cells under various environmental stress conditions. Recently, the emergence of a range of non-fullerene acceptor materials has led further breakthroughs in the development of solution processed organic solar cells. Compared to their fullerene-based counterparts, these materials demonstrate great promise in achieving superior device performance with significantly reduced fabrication costs. Furthermore, while fullerenes are known to be linked with a number of major degradation mechanisms of organic solar cells particularly under light and thermal stress conditions, the use of non-fullerene acceptors instead of fullerenes represents a unique opportunity to address the stability challenge of organic solar cells. In this talk, author will combine a number of advanced characterization techniques to investigate the degradation of both fullerene-based and fullerene-free solution processed organic solar cells under various degradation environments especially under light, oxygen and thermal stress conditions, and demonstrate how a better understanding of the degradation mechanisms of their performance lead to improved materials and device design for improved solar cell stability, thereby significantly enhancing their commercialization potential of both types of organic solar cells.

Lahmar Abdelilah

University of Picardie Jules Verne, France

Title: Enhanced magnetization in the BiFeO3-RMnO3 thin films

Biography:

Lahmar Abdelilah received his Doctorate in Science in Materials Chemistry in 2007 from University of La Rochelle (France)/University Mohammed V (Morocco). Subsequently he worked at the Institute for Materials and Surface Technology (IMST) in Kiel (Germany) until 2012. Then he moved to Amiens, in Laboratory of Condensed Matter Physics, where he obtained his Habilitation thesis in 2017. His research interests encompass a broad range of multifunctional materials (multiferroic, electrocaloric, and magnetoelectrics). He has published more than 50 papers published in peer reviewed journals and contributed to numerous international conferences.

Abstract:

The monolithic BiFeO₃ (BFO) is claimed to be multiferroic at room temperature, but only a weak magnetization and moderate polarization are observed. The co-doping of BFO is a way to improve electrical properties as well as magnetization. Thin films of the BiFeO₃-RMnO₃ (R = rare earth) system affords an interesting combination of good ferroelectric polarization and magnetization properties at room temperature that are a prerequisite for intrinsic multiferroism. Particularly, the addition of GdMnO₃ leads to a substantial increase in magnetization that experimentally allows the determination of Néel temperature (TN). The origin of magnetization improvement will be discussed in terms of Gd substitution effects on octahedral distortion and tilting.

Chair

Consiglia Mocerino

Sapienza University of Rome-MIUR, Italy

Co-Chair

Dmytro A Bozhko

Universität Kaiserslautern, Germany

Session Introduction

Fedor Pudonin

P.N. Lebedev Physical Institute of RAS, Russia

Title: Nanoisland magnetic films: Technology and possible applications

Biography:

Fedor Pudonin is the Head of Laboratory in P.N.Lebedev Physical Institute Russian Academy of Science, Russia. He is the chief researcher in the Laboratory of Heterogeneous Systems Physics.

Abstract:

Now there has been a significant interest in the technology of obtaining and studying magnetic nanoisland films. This is due both to the enormous applied potential of these objects. We used the RF-sputtering method to obtain nanoisland films of magnetic materials such as FeNi, Co, Ni, etc. In this report we will present the results of our work on obtaining magnetic nanoisland films and some applied aspects of these structures. Since the deposition rate is a stable value at constant technological parameters, we deposit thin films whose effective thickness was determined by the time of deposition. There is a critical thickness d*(percolation threshold) below which the films are nanoisland, and films with effective thickness d>d* become continuous. To determine the d* value, we have grown several series of FeNi films with effective thicknesses from 0.5 to 3.0 nm with thickness steps Δ~0.07 nm. The standard polished ceramic plates (sitall), crystalline silicon, silicon nitride, glass, as well as thin Al₂O₃ layers deposited on silicon were used as substrates. Figure 1 shows an image of some island FeNi films. To determine d*, the dependences of the permittivity e(w) and conductivity s on the thickness were studied. It was found that Re e(w) and δ=[σ (T=300 K) - σ(T=77 K) simultaneously change sign at d~1.6-1.8 nm, which indicates the presence of a percolation transition at d*~1.6-1.8 nm. Thus, FeNi films with an effective thickness d<1.6 nm are island. We have shown that photoconductivity in the range 500-1500 nm, anomalous conductivity in weak electric fields, giant dielectric constant, and other unusual properties are observed in nanoisland films of FeNi and other metals. We proposed to use nanoisland FeNi films in which the effect of anomalous conductivity is observed as labels that can serve as a protection for various documents and securities and other products. Nanoisland films can also be used to create sensors of superweak magnetic fields at room temperature. For this, we fabricated multilayer island structures such as [FeNi/Co]_N in figure 2. With the help of X-ray studies it was shown that in such systems the island layers do not mix and they really are periodic structures. It was found that these structures are capable of detecting (changing their resistance) magnetic fields H<10^-11 T. This is a great result and we hope to improve it.

Consiglia Mocerino

Sapienza University of Rome—MIUR, Italy

Title: Efficiency of nanotechnologies in the high performance of buildings

Biography:

Consiglia Mocerino, graduated cum laude with a Master of Science degree in Architecture, Ph.D. in Urban Recovery and Regeneration and specialist in Restoration of monuments, has held at the Faculty of Architecture, Sapienza University of Rome, teaching and research collaboration and teaching assignments, as a contract professor, in Architectural Technology. In the same Faculty she obtained the nomination of subject expert in the discipline of Technology of Architecture and Industrial Design. She is an expert in research on issues related to innovation and technological experimentation of systems and products in efficient, intelligent, low impact, environmentally friendly architectures, innovative materials and the application of third generation nanotechnologies.

Abstract:

New research in the field of technological innovation, with nanotechnologies and nano-structured eco-active materials, smart materials that change according to meteorological and atmospheric flows, with new adaptive and smart models, etc. identify new processes in the efficient building of infrastructures in cities and territories, with low environmental impact and reduction of CO₂. Objectives of innovation and sustainability with use of functional materials that mainly focus on optical, magnetic, electrical properties, such as those of semiconductor, magnetic materials, etc. with the dematerialized technologies and high performance in the building and use of sustainable materials with high solar transmittance, lightness, air quality and low thermal conductivity. So methodologies with the application of efficient nanostructured materials including silica aerogels, the doped materials by epoxy resins with carbon nanotubes (CNT), much stronger than steel, intelligent bio phase change materials (PCM), bioplastics, etc. Application of advanced materials such as aerographite, based on carbon nanotubes, with characteristics of resilience, strength, flexibility and durability, aimed at different uses in the building sector of the construction industry, for super-light energy accumulators, for purification devices of air and water. Distinguishing materials by environmental quality since recyclable, renewable and biodegradable, linked to chemical/physical, mechanical and technological, while denouncing criticality and application limits for the protection of human health. High performance requirements of architectural beauty even through transparency and surface gloss, with nanostructured materials ecoactive high performance, glassy and light-sensitive materials, iridescent and translucent colors, from thermal comfort with use of minimum thickness. The challenge is in the application of advanced materials in the emerging areas of digital fabrication for environmental sustainability and in the efficient, intelligent and sustainable building sector.

Victor V Sokolov

MIREA— Russian Technological University, Russia

Title: Macroscopic dynamics of ferrofluids

Biography:

Victor V Sokolov is a Professor at MIREA-Russian Technological University, Russia. His activities and awards include the Russian Government Premium in Education (2013), Honoured Worker of Higher Education of the Russian Federation (2003), Certificate of Soros's Associate Professor of Physics (1998). He is a Member of the Russian National Committee on Theoretical and Applied Mechanics. His research interests lie in macroscopic theory of continuum with frozen-in magnetization and Hamiltonian dynamics of complex fluids.

Abstract:

Ferrofluids (magnetic fluids, magnetic nanofluids) are ultrastable colloidal suspensions of magnetic nanoparticles in non-polar and polar carrier liquids. The most striking feature of a ferrofluid is that it is a liquid with strong magnetic properties. The macroscopic dynamics of ferrofluids remains a subject of interest. Here we concentrate mainly on the two limiting cases. One corresponds to the assumption about equilibrium magnetization of ferrofluids i.e., under dynamic perturbations of the ferrofluids, the relaxation time of a magnetic field strength to its equilibrium value is infinitely small. Another limiting case corresponds to the assumption of frozen-in magnetization. The relaxation time of a magnetic field strength to its equilibrium value is infinitely large. The physical grounds for introducing this limiting case were descriptions of dynamic processes, in particular, ultrasound propagation in ferrofluids. The obtained expression for the velocity of fast magnetosonic waves describes the existing experimental data on the anisotropy of ultrasound wave propagation in ferrofluids. The previous theories could not describe the propagation of ultrasound waves in magnetic fluid under external magnetic field. The prediction concerning the existence of new waves, namely slow magnetosonic wave and Alfvén-type wave in ferrofluids seems very important and requires an experimental verification. We believe these waves would prove a most prolific area of experimental research.

Vladyslav O Cheranovskii

V.N. Karazin Kharkiv National University, Ukraine

Title: The electron correlation effect on the magnetic properties of quasi-one dimensionalmaterials on the base of graphitic nanoclusters with embedded transition metals

Biography:

Vladyslav O Cheranovskii has completed his Doctor of Sciences in the year 1994 from Institute for Single Crystal. He is the Professor of V.N.Karazin Kharkiv National University, Department of Chemistry. He has published 49 papers recognized by Scopus and Web of Science databases. He is working in field of Solid State Physics and Quantum Chemistry. His main subject of interests includes strongly correlated electron system quantum theoretical simulation of electron structure and thermodynamics of nanomagnets.

Abstract:

It is well known, the phase diagrams of the nanostructured magnetic materials demonstrate a variety of low-spin and high-spin states. The switch ability of these states is the central point to potential applications in molecular spintronics and high-density magnetic data storage. In this work, we studied the energy spectrum and thermodynamics of quantum Heisenberg spin model for graphitic nanoribbons with periodically embedded heteroatoms and model chain magnets formed by triangular graphitic clusters. The exact diagonalization study, density matrix renormalization group and Quantum Monte-Carlo method based on stochastic series expansion approach were used for this purpose. We found that clusters with frustrated interactions could exhibit spin switching when the corresponding coupling parameters are changed. For several carbon nanoribbons, we found macroscopic ground state spin and intermediate magnetization plateau. We also studied the exact thermodynamics of infinite distorted nanoribbons described by the special case of Heisenberg-Ising model. Special attention was given to the doped systems described by single-band Hubbard model with strong electron repulsion at partial electron filling. Here we used cyclic spin permutation formalism to derive the corresponding low-energy lattice Hamiltonians. We found numerically the possibility of the spin switching with the change of model parameters. We also demonstrated that the correlated hopping terms, which are present in our Hamiltonians, may change significantly the lowest energy spectra of the corresponding magnets in comparison with the similar description within the framework of the t-J model.

Victor Pavlov

Ioffe Institute of Russian Academy of Sciences, Russia

Title: Photo-induced magneto-optical phenomena in magnetic semiconductors: europium chalcogenides

Biography:

Victor Pavlov has completed his PhD in the year 1993 and second PhD in the year 2007 at the Ioffe Institute, St Petersburg, Russia He is the laboratory head of optical phenomena in magnetic and semiconductor crystals He has published more than 80 papers on linear and nonlinear magneto-optical phenomena in bulk magnetically ordered materials and nanostructures.

Abstract:

Europium chalcogenides EuX (X = O, S, Se, Te) are a compact group of magnetic semiconductors with unique electronic, magnetic, optical and magneto-optical properties. The physical properties of the europium chalcogenides EuX are determined by the electronic structure of the Eu²⁺ ions, which have strongly localized 4f⁷ electrons with a large spin S = 7/2. A photo-induced Faraday effect (FE) was studied in the chalcogenides EuTe and EuSe by the optical pump-probe technique using continuous lasers and a broadband light source. The photo-induced FE was investigated as a function of the intensity of light, magnetic field, and temperature. Figure 1 shows field dependences of the photo-induced FE in EuTe at various optical pumping intensities. It has been established that resonant excitation of the 4f⁷5d⁰ → 4f⁶5d¹ optical electric-dipole transition in EuTe produces magnetic polarons with a quantum efficiency of about 10% and a magnetic moment exceeding 600 μB for EuTe and 6000 μB EuSe at low temperatures. A quantum mechanical model has been developed for calculating the photoinduced FE associated with the formation of giant magnetic polarons in EuTe. The developed theory describes well the experimentally observed dependencies. The optical pump-probe technique with a femtosecond time resolution was used to study ultrafast dynamics in EuTe near the absorption band gap. A magnetic-field-induced crossover from the inverse FE to the optical orientation was observed. In conclusion, a number of new photo-induced optical effects in magnetic semiconductors EuX were observed.

Adil Guler

Marmara University, Turkey

Title: Process, characterization and physical properties of 3d transition ion doped-tetrahedrite compounds

Biography:

Adil Guler, Lecturer, now is a Researcher in Marmara University, Ataturk Faculty of Education, Department of Computer and Instructive Technology Teacher. He completed his BSc degree in Physics and Specialist in Magnetic and Superconductive materials. He got his PhD at Marmara University, Department of Physics. He works in the research group of Prof. Dr. Arunava Gupta as a Research Scientist in Alabama State University. He also makes projects with Assist. Prof. Dr. Cihat Boyraz on superconductivity and magnetism. His magnetic superconductivity group has been working on Fe-based superconductors for 5 years.

Abstract:

The demand on new and waste energy potential increases with decreasing energy sources in the world. This situation brings new attitudes globally on using waste energy and discovering new energy sources. Among the main types of waste renewable energy, thermoelectricity which is converted electric energy from waste heat play a very important role on science and with its applications on industry. Among the many sulphate salts, the group of tetrahedrite/tennantite has potential interest in physics in many ways are widely used in thermoelectric and photovoltaic applications. The importance of the thermoelectric researches is coming from neglecting the high material costs and long-termed synthesizing procedures. On the other hand, the properties of cheapness, accesibility, minimized risk factor in the usage of thermoelectric materials make important for technological applications in scientific studies. Recently, tetrahedrite Cu₁₂Sb₄S₁₃ material doped with different dopant elements exhibits important thermoelectric properties. Tetrahedrite, Cu₁₂Sb₄S₁₃, is emerging as a promising phase in thermoelectrics. It exhibits an intrinsically low lattice thermal conductivity (κL = 0.4W m−1 K−1 at 700 K) due to unique features in its crystal structure. At the same time, the defect zinc-blende lattice ensures a good crystalline pathway for electron transport. At the same time, tetrahedrites are one of the most abundant TE minerals on Earth. In this study, main material Cu₁₂Sb₄S₁₃ tetrahedrite doped with 3d ions such as Sb and As were synthesized using solid state reaction method. The annealing procedure was optimized for Sb and As doped -Cu₁₂Sb₄S₁₃ tetrahedrite samples. Structural characterization was done by X-ray diffraction method (XRD). Scanning electron microscope (SEM) and an in-situ electron dispersive spectroscopy (EDS) were used for particle size and elemental compositions respectively. The compositions were also analyzed by electron spin resonance (EPR) and vibrating sample magnetometer (VSM) tools as shown in images.