HIFI - Sisteme nanostructurate cu aplicatii in dispozitive de inalta frecventa


Romanian version - versiunea în limba română

Sisteme nanostructurate cu aplicatii in dispozitive de inalta frecventa

Proiectul Sisteme nanostructurate cu aplicatii in dispozitive de inalta frecventa - HIFI este dedicat cercetarii stiintifice in domeniul materialelor multifunctionale nanostructurate si studierii posibilitatilor de utilizare ale acestora in dispozitivele de inalta frecventa.

Utilizarea materialelor magnetice in dispozitivele pasive de microunde este datorata in special valorilor ridicate a permeabilitatii magnetice si a proprietatilor giromagnetice. Pentru a fi transparente pentru radiatiile de inalta frecventa materialele magnetice ar trebui sa fie neconductive din punct de vedere electric. Exista o serie de materiale magnetice ca Ni, Fe, Co care prezinta proprietati remarcabile pentru a fi folosite in dispozitive de microunde; fiind insa metalice ele nu pot fi folosite la aceste frecvente. Daca dimensiunile entitatilor magnetice sunt mai mici decat adancimea de patrundere a radiatiilor in aceste materiale atunci ele vor fi totusi transparente pentru radiatiile de microunde. Aceasta este ratiunea numeroaselor studii la nivel international in domeniul utilizarii materialelor magnetice metalice nanostructurate in aplicatii de inalta frecventa.
Principala dificultate existenta in realizarea unor astfel de dispozitive este dependenta fenomenelor de absorbtie de dimensiunile si distanta intre entitatile nanostructurate.

Proiectul de fata implica un studiu detaliat al fenomenelor care influenteaza in mod esential comportarea sistemelor magnetice nanostructurate, in special a sistemelor de nanofire metalice feromagnetice, la frecvente inalte. Rezonanta feromagnetica a particulelor magnetice depinde puternic de marimea si forma acestora. In sisteme particulate ce interactioneaza prin interactiuni de schimb si/sau magnetostatice, nivelul acestora este un factor ce influenteaza raspunsul in frecventa al ansamblului. Pentru a realiza un control cat mai fin al proprietatilor unui mediu, solutia tehnologica optima este folosirea nanostructurarii. Particulele feromagnetice, avand aproximativ aceeasi forma si volum sunt asamblate intr-o retea geometrica perfecta. Avantajul unei astfel de configuratii consta in controlul proprietatilor magnetice prin cel al caracteristicilor geometrice. Pentru a reusi insa proiectarea unor dispozitive cu anumite proprietati pre-definite, trebuie sa intelegem profund modul in care interactiunile influenteaza comportarea ansamblului. Proiectul implica o ampla latura experimentala ce consta in realizarea sistelelor de nanofire, masuratori magnetice statice si la inalta frecveta pe sistemele de nanofire, depuneri de straturi metalice si dielectrice pe sistemele planare nanostructurate, realizarea si caracterizarea dispozitivelor de microunde proiectate. Aceasta latura experimentala este permanent insotita de o importanta latura de modelare iar in final de proiectare a materialului cu anumite proprietati utile in aplicatii.

Acest proiect va avea ca principal rezultat analiza experimentala si modelarea numerica a unei largi categorii de materiale nano-structurate pentru a evidentia modalitati practice de proiectare si realizare a unor elemente utile in aplicatii de inalta frecventa.

English version - versiunea în limba engleză

Nanostructured systems with applications in high-frequency applications

The project Nanostructured systems with applications in high-frequency applications is dedicated to the scientific research in the domain of nanostructured multifunctional materials and to the study of the possible use of these materials in high frequency devices.

The project has a strong scientific part which consists in the study of the phenomena that influence essentially the nanostructured magnetic systems behavior, especially of the ferromagnetic metallic nanowires, at high frequency. The ferromagnetic resonance of magnetic particles strongly depends on their size and shape. In particulate systems with exchange and/or magnetostatic interactions, the intensity of interactions is a decisive factor in the frequency output of the ensemble. To obtain the fine control of the properties of a medium, the optimal technological solution is nanostructuring. The ferromagnetic particles, with virtually the same shape and volume, are assembled in an almost perfect geometrical network. The advantage of such a configuration consists in the control of magnetic properties through geometrical characteristics. However, in order to succeed in designing devices with pre-determined properties one have to profoundly understand the way in which the interactions are influencing the ensemble behavior.

The project implies an ample experimental part which consists in the production of nanowire systems, static and dynamic magnetic measurements on systems of nanowires, production and characterization of designed microwave devices. This experimental part is continuously accompanied by a strong modeling activity and finally by the design of a material with some properties found useful in applications. We shall use micromagnetic models for the calculation of the ferromagnetic resonance in isolated particles/wires. The effect of interactions will be considered through physical and phenomenological modeling, in order to increase numerical efficiency.

This project will have as a main result the experimental analysis and numerical modeling of a wide category of nanostructured materials to evidence practical ways of design and production of useful elements in high frequency applications.

 

MODx - Mollio