Numeričko modeliranje lokalne strukture kompleksnih materijala

master's thesis

• Title (english): Numerical modeling of the local structure of complex materials
• Author: Danijel Skeledžija
• Mentor: Damjan Pelc (mentor)
• Committee member: Damjan Pelc (predsjednik povjerenstva)
• Committee member: Ivan Kokanović (član povjerenstva)
• Committee member: Andrej Novak (član povjerenstva)
• Committee member: Mario Novak (član povjerenstva)
• Committee member: Mihael Srđan Grbić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2023-10-20, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U mnogim važnim materijalima pojavljuju se kratkodosežne strukturne fluktuacije koje dovode do lokalnih odstupanja od prosječne kristalne strukture. Takva nehomogenost na nanoskali je često ključna za razumijevanje termalnih i elektronskih svojstava materijala, no općenito ju je mnogo teže proučavati nego dugodosežne kristalne strukture. Takva lokalna odstupanja uzrokuju difuzno raspršenje te je zbog toga proučavanje difuznog raspršenja ključ za razumijevanje lokalne strukture nekog materijala. U ovom radu ukratko će se objasniti teorija difuznog raspršenja te će se pomoću Monte Carlo tehnika i drugih simulacija numerički istraživati različite konfiguracije lokalnog nereda u materijalima sa strukturom na bazi perovskita. Time će se postići kvalitativno razumijevanje nehomogenosti u širokoj klasi materijala (rezultati simulacija bit će primjenjivi i na ostale spojevi s istom strukturom kao što su neki kuprati), te postaviti temelj za kvantitativne analize. Rezultate simulacija usporedit ćemo s mjerenjima difuznog raspršenja za neutrone i x-zrake za stroncijev rutenat, Sr2RuO4. Stroncijev rutenat je kristal iz skupine perovskita čije supravodljivo stanje i nakon brojnih godina istraživanja i dalje nije u potpunosti jasno te postoji velik interes za istraživanjem ovog spoja.

Abstract (english)

Many important materials exhibit short-range structural fluctuations which cause local deviations from the average crystal structure. Such inhomogenity on the nanoscale is usually the key to understanding the thermal and electronic properties of materials, but it is much harder to observe than long range crystal structure. Such local deviations cause diffuse scattering and that is why researching diffuse scattering is the key to understanding local structure of materials. This thesis will explain the theory behind diffuse scattering and with the help of Monte Carlo simulations and other techniques we will explore local disorder in perovskite materials. In this way we will achieve qualitative understanding of inhomogenity in a wide class of materials (the results will be applicable on all materials with the same structure such as some cuprates) and we will make a foundation for quantitave analysis. The results of our simulations will be compared to the neutron and x-ray diffuse scattering measurements for strontium ruthenate, Sr2RuO4. Strontium ruthenate has a perovskite-based crystal structure and its superconducting state is still not fully understood after years of research which is why this material still attracts considerable attention.

• Keywords: difuzno raspršenje; Monte Carlo simulacija; stroncijev rutenat
• Language: croatian
• URN:NBN: urn:nbn:hr:217:743316
• Study programme: Title: The University Integrated Undergraduate and Graduate Programme in Physics; Research Physics; specializations in: Research Physics; Course: Research Physics; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: sveučilišni magistar fizike (sveučilišni magistar fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-10-20
• Created on: 2024-01-26 12:35:00