BULGARIAN SCIENCE FUND
Contract No КП06-Н28-9-2
Topic: Effects of resistive switching and magneto resistance in transition metal (Co, Ni, Fe) doped ZnO layers for multifunctional applications
Coordinator: Prof. DSc. Albena Paskaleva
Duration: 12.2018 – 12.2021
The wide spread in the recent years of portable digital devices defined the significant interest of the semiconductor industry to non-volatile memory (NVM) technology. Novel memory concepts totally different from that based on charge-storage are especially attractive for the next-generation nonvolatile memories. Resistive random access memory (ReRAM) is considered as one of the most promising candidates among them because it offers some attractive advantages in respect to the floating gate technology. Magnetic memories based on magnetoresistance effect are another very intensively investigated concept for realization of “non-charge” based storage devices. Further important step in the process of enhancing the data storage densities is the realization of multifunctional device, i.e. simultaneous electrical tuning of multiple physical properties. A realistic approach to meet the demands is the electrical control of the magnetic and resistance properties which is of great interest not only for technological applications but also for fundamental physics. It is a great challenge for simultaneous realization of large memristance and magnetoresistance in one nanoscale junction, because it is very hard to find a proper layer which not only serves as good insulating layer for magnetoresistance but also easily switches between high and low resistance states under electrical field. In addition, this device should operate at room temperature which is additional challenge what concerns magnetoresistive effect. The purpose of the project is to obtain by atomic layer deposition (ALD) ZnO films doped with different 3d transition metal elements (Co, Ni, Fe) as possible materials for application in multifunctional memory and sensor devices. Resistive switching effects, magnetic properties and magnetoresistance will be systematically studied in dependence on dopant, structure and process parameters. The project aims at in-depth analysis and understanding of fundamental processes and phenomena at the origin of RS and magnetoresistance in doped ZnO layers and their intimate interplay. The ultimate goal is to elaborate Metal/ZnO-based/Metal structures where the materials are developed and optimized to stabilize simultaneous resistive switching and magnetoresistance at room temperature and the system behaves as a memristor, in which the state variable is the magnetic moment in addition to the resistance.
Contract No ДН08-7/13.12.2016
Topic: Mechanical and electrical properties of model lipid membranes in the presence of biologically active substances
Coordinator: Assoc. Prof. Victoria Vitkova, PhD
The understanding of basic mechanisms driving some vital processes in biological cells requires a detailed knowledge of mechanics and electrostatics of biomembranes. The main objective is to first establish concerted and multifaceted investigation of these properties using a set of model lipid membranes and applying complementary techniques (fluctuation analysis on lipid vesicles, electrochemical impedance spectroscopy on planar lipid bilayers, etc.), and second, to evaluate how these properties are affected by biochemically relevant molecules. Synthetic bilayers will be studied in the presence of substances of practical importance for the pharmacology and food industry. The successful accomplishment of the research project will produce new scientific knowledge on the mechanical and electrical properties of biomimetic model systems as a result of combining a multidisciplinary approach, extensive scientific expertise and advanced methodology.
Contract No ДН08-2/13.12.2016 г.
Topic: Liquid crystal approach for model lipid membrane functions optimization by nanoparticles insertion
Coordinator: Assoc. prof. PhD Julia Genova
In the present project we plan experimental and theoretical investigations of the properties of lipid molecular aggregates by inclusions of organic and non-organic nano-particles and bio active molecules. The role of the hydrogen bonds for stabilization the structure and the functions of the provoked by the inclusions complex liquids, in particular lipid membranes and dimeric liquid crystals, will be studied. The resemblance of the lipid membranes (with long range liquid crystal order) and the dimeric liquid crystals, determines by the availability of the nets of the hydrogen bonds in the two systems. This fact premises the liquid crystal approach, for theoretical interpretation of the lipid membrane experimental data, to be applied. The project implementation will be realized by specialists on structural and electrooptical properties of the liquid crystals, including dimeric liquid crystals and their nanocomosites, in collaboration with specialists on structural and physical properties of the bi-layer lipid membranes and vesicules. The basic organization of the project posses the necessary for the implementation of the project experimental base and corresponding infra structure. Unique experimental sets and technologies for the investigation of the mechanical properties of the bi-layer lipid membranes are available. The signification of the hydrogen bond for the mechanical properties of the lipid membrane is one of the expected results. The training up of the young scientists, included in the project, will be one of the basic tasks.
Contract No ДН08-16/14.12.2016
Topic: “Laser induced fabrication of three dimensional nanoparticle structures and study of their optical properties”
Coordinator: Ekaterina Iordanova
Duration: 12.2016 – 12.2019
The presented research project is focused on the fundamental physical background of a laser assisted method for fabrication of noble metal nanoparticles into transparent materials and study of the optical properties of complex nanoparticle structures. The main activities are directed to the revealing of the mechanisms of laser-composite materials interaction and laser induced complex nanoparticles structure formation. The main activities in the presented project are directed to study of the fundamentals of a method for fabrication of complex 3D nanoparticle systems embedded into dielectric matrixes. The method is based on photo induced reduction of metal ions embedded into silicate glasses. The main objects of interest are the mechanisms playing role in the particle formation and dynamics and the influence of the processing conditions. This knowledge will give opportunity of fabrication of structures with desired and controllable characteristics. The well developed methods for 3D laser scanning will turn this method into a high efficient in fabrication of complex composite materials that has no alternatives at the present. The formation of such materials will facilitate the experimental study of their optical properties, the description of the mechanisms of interaction of such systems with the electromagnetic field and the characteristics of the field in their near field zone.
Contract No ДН 18/14 – 12.12.2017
Topic: Composite and adiabatic methods for control in quantum and optical technologies
Coordinator: Assoc. Prof. Dr. Emiliya Dimova, PhD
Duration: 12.2017 – 12.2020
The present project is dedicated on the development of new methods for coherent control of quantum states on the samples of ultra-cold atoms and on the application of the laws of quantum physics in classical optics for the creation of new technologies. The successful realization of the project is guaranteed by the close collaboration between both teams: the theoretical team developing the basic methods and experimental team with good expertise in the implementation of the proposed new methods. Moreover, through this project the research groups from different scientific institutions is consolidated. This enables the exchange of knowledge, technology and equipment. As a result, It leads to improving the qualifications of the team members and the project attracted more students and PhD students. Theoretical methodology involves several basic methods of theoretical and mathematical physics that allow analytical and numerical description of discrete quantum systems. It covers areas such as: classical and quantum optics, quantum coherent control metamaterials, nonlinear optics, etc. The experimental realizations is based on the manipulation of coherent states of rubidium atoms, cooled to tens of micro-kelvin, and the realization of new optical components. New methods of coherent control of quantum states of atoms will be produced. New methods for the realization of optical devices, for example broadband optical components, will be molded.
Cooperation project between the Institute of Solid State Physics – the Bulgarian Academy of Sciences, Sofia, Bulgaria and the Joint Institute for Nuclear Research (JINR), Dubna, Russian Federation
Тема: Investigation of the influence of nanoparticles on the properties of biologically relevant systems
Ръководител: Assoc. prof. PhD Julia Genova
In the present project we plan experimental and theoretical investigations of the physical and structural properties of biologically relevant systems and modification of these properties by incorporation of organic and non-organic nano-particles and bio active molecules, including carbon nanostructures, cholesterol, proteins and others. Typical structural methods for studying the specific physical characteristics properties of complex systems involving Fourier transform infrared (FT-IR), polarization micro-Raman spectroscopy, differential scanning calorimetry (DSC), thermally induced shape fluctuations analysis (TISFA), atomic-force microscopy (AFM) will be used. The evaluation of the standard physical parameters, like enthalpy, energy, entropy gives us possibility to apply molecular dynamic simulation for assignment of the new physical and structural characteristics of the complex lipid systems. The project implementation will be realized by specialists on mechanical and structural properties of bilayer lipid membranes and vesicles, structural and electrooptical properties of condensed matter, with specialists on computer modelling.