Day 1 :
Keynote Forum
Fedor Pudonin
P.N. Lebedev Physical Institute of RAS, Russia
Keynote: Unusual properties of multilayer nanoisland magnetic systems: Supervortices, flat spin springs and optical nonreciprocity
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:
The paper presents the results of studies of original nanostructures - multilayer systems from magnetic nanoislands of the (FeNi/Co)N type. Earlier in the metal nanoislands, we found photoconductivity in a wide spectral range (0.4-1.5 μm), anomalous conductivity, etc. It was also found that those systems can detect at room temperature superweak magnetic fields H of less than 10-11T. The physical reasons for this high sensitivity are not fully understood, but it is clear that they are due to the unusual physical properties of island systems. Metal nanoisland layers with a given effective thickness were grown by RF sputtering. For metal films, a percolation threshold was found - d* (for FeNi and Co films d*~1.8 nm). Films for d<d* were island, and d>d* - continuous. Nanoisland were flat pancakes of rounded shape with lateral dimensions of 3-30 nm, and their effective thickness varied from 0.4 to 7.0 nm. Magnetization processes were investigated at room temperature by the magneto-optical Kerr effect (MOKE). In the structures (FeNi/Co)N (N varied from 10 to 40), unidirectional magnetic anisotropy was observed, not associated with the well-known exchange anisotropy (the hysteresis loops did not have an exchange shift). It was suggested that the detected unidirectional anisotropy is associated with the appearance in the structures of an unusual supervortical magnetization. In this case the vortex is not concentrated in separate nanoislands, but is distributed over a certain set of them. Micromagnetic modeling confirmed the possibility of the existence of a supervortical magnetization in the island structure. An indirect confirmation of the existence of such unusual supervortical magnetization was the results of a study of the magnetization of the nanoislands layers on a SQUID magnetometer. The presence of a supervortical magnetization leads the island structures to be chiral and leads to the appearance of an anomalous optical nonreciprocity. In this report we discuss the possible causes of the appearance of optical nonreciprocity. However, the high sensitivity of island structures to superweak magnetic fields, apparently, is not related to supervortex magnetization. For this reason magnetization processes and magnetoresistance in special structures - bilayers [(FeNi/Co)-Al2O3]N were investigated. A region with specific magnetization in FeNi nanoislands in a weak magnetic field is appeared. In those regions of FeNi islands the rotation of the magnetization vector is occurred. Those regions we call a flat (two dimensions) spin springs. When the current flows through this region, additional scattering of the electron spins takes place and an additional negative magnetoresistance occurs. We believe that these spin springs can cause high sensitivity of island structures to weak magnetic fields.
Keynote Forum
Consiglia Mocerino
Sapienza University of Rome—MIUR, Italy
Keynote: Sustainability of nanomaterials in architecture
Biography:
Consiglia Mocerino graduated Cum Laude with a Master of Science Degree in Architecture, PhD in Urban Recovery and Regeneration and is a Specialist in Restoration of Monuments. She has held teaching, research collaboration and teaching assignments, as a Contract Professor, in Architectural at the Faculty of Architecture, Sapienza University of Rome. In the same faculty she obtained the nomination of Expert (3rd Member of the Examining Commission), 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 nanotechnology, IT, and intelligent robot in architecture. Her research interests include 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, IT, and intelligent robot in architecture.
Abstract:
The nanomaterials that represent the technological innovation in the building industry are in a growing development, based above all on high performances of environmental sustainability and safety for managers and workers in the building sector and for end users. Hence, HenceHe nnew nanomaterials in architectures, such as in IT, electronics, healthcare, textiles, design, etc., are launched by improving chain production, with low environmental impact, for the protection of human health, excluding the possible risk of their probable toxicity—the identified toxicity and exposure identified in both humans and the environment. They are defined by the EU recommendation (2011/696/EU), adopted by REACH for registration, evaluation, authorization, restriction of chemicals and by CDL for classification and labeling as, "a natural, accidental or manufactured material containing free, aggregate or agglomerated particles in which, for 50% or more of the particles in the numerical dimensional distribution, where one or more external dimensions are in the range of dimensions 1 nm: 100 nm". This promising sector of the economy has become one of the strongest themes for studies and research, for universities, R&D, FIEC and FETBB and for national and international debates paying attention, mainly, to the chemical analysis and their life cycle up to the recycling of waste, to the awareness of the use and of useful instruments with necessary measures to be adopted. In fact, the physico-chemical properties of engineered or synthetic particles can differ from those of soluble and insoluble type, indicating the latter, and the most interested in the use of nanotechnologies and among the most susceptible to thermal effects, while focusing research on soluble particles, despite their easy dispersion in the environment. Therefore, objectives of conformity of the use of nanomaterials in different contexts with sustainable criteria for the environment and for human health, with improvement of production, safety and conscious application. Hence, strategies for monitoring and use of imagining techniques with application of ECHA, EUON Observatory with NanoData and NanoMapper, etc. The methodologies indicate the application of materials enhanced by nanoparticles such as self-cleaning cements with the ability to absorb CO2 emissions, ceramics, coatings, insulators, etc. The challenge in architecture is the improvement with conscious use of the materials we have designed in all the components of the building and the implementation of testing their technical performances.
Keynote Forum
Vladyslav O Cheranovskii
V.N. Karazin Kharkiv National University, Ukraine
Keynote: Peculiarities of the energy spectrum and the magnetic properties of strongly correlated electron systems on bipartite lattices formed by weakly interacting linear segments
Biography:
Vladyslav O Cheranovskii 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 interest includes strongly correlated electron system quantum theoretical simulation of electron structure and thermodynamics of nanomagnets.
Abstract:
It is known that the intermediate plateau in field dependence of magnetization is informative characteristic for molecular ferrimagnets and some frustrated spin systems. We demonstrate the existence of intermediate magnetization plateau for a family of one-dimensional bipartite (non-frustrated) spin systems formed by weakly interacting segments and having singlet ground state. In the limit of weak interactions between segments these systems have a similar structure of the lowest part of the energy spectra and we presented simple description for above magnetization plateaus by means of perturbation theory. The increase of the interactions between segments leads to significant modification in the energy spectra and the magnetization curves for our systems. We studied this process numerically by the density matrix renormalization (DMRG) and Quantum Monte-Carlo (QMC) methods. We also performed numerical studies of the spin-Peierls instability for our systems and estimated the corresponding critical exponents for the ground state energy. We studied magnetic properties of the electron systems on finite 2-leg ladder rings formed by weakly interacting rungs and described by infinite-repulsion Hubbard model. For the numerical and analytical study of the lowest energy states of the above systems, we used cyclic spin permutation formalism. We found the possibility of jump-wise change of the ground state spin with the increase of the interaction between rungs. To explain this finite size effect, we derive new modification of magnetic polaron approximation, which agrees well with the results of the exact diagonalization study.
Keynote Forum
Rafał Michalski
Atomic Systems Ltd., Poland
Keynote: Simulated thermomagnetic properties of DyAl2, HoAl2 and ErAl2 compounds calculated by atomic matters MFA computation system
Biography:
RafaÅ‚ Michalski graduated in 1996 from the Pedagogical of University Krakow, Poland in the department of Physics, Mathematics and Computer science. He worked in the Institute of Physics and Computer Science as an Assistant Professor (1996-2001) and then in 2001 he gained a Ph.D in physics in the department of Nuclear Physics and Solid State Physics at Krakow University of Mining and Metallurgy (AGH). Subsequently, he became an associate professor. His PhD Thesis was “Calculations of the thermal evolution properties of 4f-electron compounds with the use of the self-consistent methods”. In 2001, dr R. Michalski become a leader of a Polish Scientific Research Committee project (no 1463/P03/2002/22) entitled “The Effects of crystalline symmetry in ThCr2Si2 type Rare Earth compounds”. The project ended 31.12.2002. Simultaneously, he worked at the Center for Solid State Physics with prof R.J. RadwaÅ„ski (1996-2006) and published around 30 papers about Crystal Field (CEF) and spin-orbit coupling (SO) effects in materials. At the same time, R. Michalski created two free access computing packages: BIREC (Basic Interactions in Rare-Earth Compounds) and CEF for 3d ions (Crystal Electric Field for 3d ions) to simulate the fine electronic structure and examine the consequences of such a structure on properties of solids as a function of temperature. In 2006-2011 R. Michalski cooperated with a consulting company providing services for industry research projects and deployment of innovative technologies. During this time he invented some commercial technologies protected by 5 patent applications in the EU and the USA. In 2012, he set up and worked for a Light Source Photometry Laboratory for MILOO Electronics. In 2008, R. Michalski started his own commercial scientific activity and developed a project co-financed by European Union resources of the regional development fund (UDA-POIG.01.04.00-12-069/10-00) entitled: “Creation of tools for comprehensive analysis of magnetic properties of elements”. The result of this project was an application called Atomic Matters, which simulates the influence of crystal lattice charge surroundings on any atom/ion from the periodic table (www.atomicmatters.eu). Atomic Matters is designed to calculate, simulate and visualize the most relevant properties of materials which are determined by the fine electronic structure of contained ions or atoms in defined conditions. After completing this project, R. Michalski lead a team of programmers in the creation of ATOMIC MATTERS MFA software. ATOMIC MATTERS MFA is an extension of Atomic Matters for magnetic phase transition simulation by self-consistent calculations according to Mean Field Approximation methodology. The synergy of both applications makes it possible to predict the macroscopic properties of materials in user-defined temperature region by using the physical properties of atomic electron systems under the influence of an external magnetic field. The visual form of the results of calculations (including full 3D interactive CEF potential visualization), intuitive interface and tools, and comparative data makes the application extremely efficient and easy for new users. The premiere presentation of ATOMIC MATTERS MFA software was at Thermag VII, the Seventh IIF-IIR International Conference on Magnetic Refrigeration at Room Temperature, Torino Italy, 11-14 September 2016. R. Michalski has managed and participated in about 20 scientific projects. He is has authored more than 40 articles published in international journals and conference proceedings.
Abstract:
We present the results of calculations of magnetic properties of three compounds from Laves phase C15 family: DyAl2, HoAl2 and ErAl2 performed with a new computation system called atomic matters MFA. We compare these results with the recently published results for TbAl2, GdAl2 and SmAl2. The calculation methodology was based on the localized electron approach applied to describe the thermal evolution electronic structure of rare-earth R3+ ions over a wide temperature range and to compute magnetocaloric effect (MCE). Thermomagnetic properties were calculated based on the fine electronic structure of 4f9, 4f10 and 4f11 configurations of the Dy3+, Ho3+, Er3+ ions, respectively. Our calculations yield the magnetic moment value and direction; single-crystalline magnetization curves in zero field and external magnetic field applied in various directions of m(T, Bext); the 4f-electronic components of specific heat c4f(T, Bext); and temperature dependence of the magnetic entropy and isothermal entropy change with external magnetic field -ï„S(T, Bext). The cubic CEF parameter values used for DyAl2 calculations are taken from earlier research of A.L. Lima, A.O. Tsokol and recalculated for universal cubic parameters (Amn) for the RAl2 series. Our studies reveal the importance of multipolar charge interactions when describing thermomagnetic properties of real 4f electronic systems and the effectiveness of an applied self-consistent molecular field in calculations for magnetic phase transition simulation.
- Magnetism | Electromagnetism | Spintronics | Materials Science
Location: Olimpica 3+4
Chair
Fedor Pudonin
P.N. Lebedev Physical Institute of RAS, Russia
Co-Chair
Karine Chesnel
Brigham Young University, USA