prikaz prve stranice dokumenta Istraživanje dinamike rešetke u stroncijevom titanatu
Embargo period 2025-11-24
master's thesis
Istraživanje dinamike rešetke u stroncijevom titanatu
Zagreb: University of Zagreb, Faculty of Science, 2023. urn:nbn:hr:217:210638
Somun, Noah
University of Zagreb
Faculty of Science
Department of Physics

Institutional repository: Repository of the Faculty of Science

Cite this document

Somun, N. (2023). Istraživanje dinamike rešetke u stroncijevom titanatu (Master's thesis). Zagreb: University of Zagreb, Faculty of Science. Retrieved from https://urn.nsk.hr/urn:nbn:hr:217:210638

Somun, Noah. "Istraživanje dinamike rešetke u stroncijevom titanatu." Master's thesis, University of Zagreb, Faculty of Science, 2023. https://urn.nsk.hr/urn:nbn:hr:217:210638

Somun, Noah. "Istraživanje dinamike rešetke u stroncijevom titanatu." Master's thesis, University of Zagreb, Faculty of Science, 2023. https://urn.nsk.hr/urn:nbn:hr:217:210638

Somun, N. (2023). 'Istraživanje dinamike rešetke u stroncijevom titanatu', Master's thesis, University of Zagreb, Faculty of Science, accessed 19 December 2024, https://urn.nsk.hr/urn:nbn:hr:217:210638

Somun N. Istraživanje dinamike rešetke u stroncijevom titanatu [Master's thesis]. Zagreb: University of Zagreb, Faculty of Science; 2023 [cited 2024 December 19] Available at: https://urn.nsk.hr/urn:nbn:hr:217:210638

N. Somun, "Istraživanje dinamike rešetke u stroncijevom titanatu", Master's thesis, University of Zagreb, Faculty of Science, Zagreb, 2023. Available at: https://urn.nsk.hr/urn:nbn:hr:217:210638

Metadata
TitleIstraživanje dinamike rešetke u stroncijevom titanatu
Title (english)Investigation of lattice dynamics in strontium titanate
AuthorNoah Somun
MentorDamjan Pelc (mentor)
Committee memberDamjan Pelc (predsjednik povjerenstva)
Committee memberDenis Sunko (član povjerenstva)
Committee memberMario Novak (član povjerenstva)
Committee memberMiroslav Požek (član povjerenstva)
Committee memberIvan Kupčić (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Science
(Department of Physics)
Zagreb
Defense date and country2023-09-01, Croatia
Scientific / art field,
discipline and subdiscipline		NATURAL SCIENCES
Physics
Abstract
U ovome radu istražujemo dinamiku rešetke nedopiranog i dopiranog (metalnog) stroncijevog titanata pomoću neelastičnog raspršenja hladnih neutrona, tijekom in situ elastične deformacije. Stroncijev titanat je kvantni paraelektrik, no primjenom naprezanja može doći do feroelektričnog uređenja. Korištena je posebno dizajnirana uniaksijalna tlačna ćelija za preciznu primjenu elastičnog naprezanja na uzorak, kako bismo proučili polarni meki mod oko točke prijelaza iz paraelektrične u feroelektričnu fazu. Neutronskim raspršenjem analizirana je disperzija mekog transverzalnog optičkog (TO) moda oko centra Brillouinove zone i njena ovisnost o primijenjenom naprezanju. U nedopiranom uzorku nije vidljiva promjena moda s naprezanjem iako je očekivano njegovo omekšavanje. U dopiranom uzorku je očekivano slično ponašanje zbog niskog dopiranja, no uočeno je povećanje frekvencije moda s naprezanjem. Diskutiramo moguće uzroke neočekivanih rezultata (manjak rezolucije, nedovoljno naprezanje, fazni prijelaz prvog reda, nagnutost kristalne rešetke) i buduća mjerenja koja bi trebala pružiti objašnjenje.
Abstract (english)
In this study we investigate lattice dynamics of undoped and doped (metallic) strontium titanate using inelastic cold neutron scattering, with in situ elastic deformation. Strontium titanate is a quantum paraelectric, but with the application of stress, it can undergo a transition to a ferroelectric phase. A specially designed uniaxial strain cell was used for precise application of elastic stress to the sample, to study the polar soft mode around the paraelectric-ferroelectric transition point. The dispersion of the soft transverse optical (TO) mode from the center of the Brillouin zone and its dependence on the applied stress were analyzed by neutron scattering. In the undoped sample, no change in mode with stress is visible, although its softening is expected. In the doped sample, similar behavior is expected due to low doping; however, it was found that the mode frequency increases with stress. We discuss possible causes of unexpected results (lack of resolution, insufficient stress, first-order phase transition, lattice tilt) and future measurements that should provide an explanation.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:217:210638
ProjectNumber: UIP-2020-02-9494
Title: Kolektivna pobuđenja i lokalna struktura u nekonvencionalnim supravodičima
Title: Collective excitations and local structure of unconventional superconductors
Acronym: CELUS
Leader: Damjan Pelc
Jurisdiction: Croatia
Funder: HRZZ
Funding stream: UIP
Study programmeTitle: 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 resourceText
File originBorn digital
Access conditionsEmbargoed access
Embargo expiration date: 2025-11-24
Terms of useLicence In copyright icon
Created on2023-11-23 11:00:50