Please use this identifier to cite or link to this item:
https://open.uns.ac.rs/handle/123456789/27895
DC Field | Value | Language |
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dc.contributor.advisor | Pantić Milan | - |
dc.contributor.author | Rutonjski Milica | - |
dc.date.accessioned | 2020-12-13T22:32:16Z | - |
dc.date.available | 2020-12-13T22:32:16Z | - |
dc.date.issued | 2011-10-07 | - |
dc.identifier.uri | https://open.uns.ac.rs/handle/123456789/27895 | - |
dc.description.abstract | <p>Cilj ove doktorske disertacije jeste da doprinese istraživanjima kvazi-dvodimenzionalnih kupratnih antiferomagneta, interesantnih prvenstveno zbog toga što toj grupi jedinjenja pripadaju „roditeljska” jedinjenja visokotemperaturskih superprovodnika. Najveća pažnja je posvećena ispitivanju magnetnih i termodinamičkih osobina La2CuO4 i Yba2Cu3O6, s obzirom da su oni u literaturi najviše izučavani, te je moguće poređenje sa eksperimentalnim rezultatima, kao i rezultatima drugih modela i drugih teorija. U računu polazimo od Hajzenbergovog hamiltonijana sa spinskom anizotropijom koji analiziramo prvenstveno u okviru metoda Grinovih funkcija (u Kalenovoj i tjablikovskoj aproksimaciji), zatim u okviru teorije linearnih spinskih talasa, a izvesna svojstva ispitivana su u aproksimaciji srednjeg polja. Karakteristike navedenih jedinjenja koje su analizirane u doktorskoj disertaciji su magnonski spektar, magnetizacija, temperatura faznog prelaza, unutrašnja energija, magnonski doprinos specifičnoj toploti i magnetna susceptibilnost. Poređenje sa eksperimentalnim rezultatima ukazuje na primenljivost metoda Grinovih funkcija u širokom temperaturskom intervalu od apsolutne nule do Nelove temperature. Takođe, zaključuje se da<br />je opravdano smatrati ova jedinjenja kvazi-dvodimenzionalnim, jer se ispostavlja da se većina svojstava neznatno menja uključivanjem u račun međuravanske interakcije. Parametar spinske anizotropije ima izražen uticaj na ponašanje ovih sistema, kao i kvantne spinske fluktuacije i kratkodometne korelacije.</p> | sr |
dc.description.abstract | <p> The aim of the thesis is to give an original contribution to the investigation of<br /> quasi-twodimensional cuprate antiferromagnets, which are interesting mainly due to the fact<br /> that high-TC parent compounds belong to the upper class of systems. The greatest attention is<br /> paid to the analysis of the magnetic and thermodynamic properties of La2CuO4 and<br /> Yba2Cu3O6, since these compounds are mostly studied in literature, enabling the comparison<br /> to the experimental results and the results obtained within other models and theories. The<br /> starting point in the calculation is the Heisenberg Hamiltonian with the spin anisotropy<br /> included, which we analyze in detail within the Green's function approach (using Callen's and<br /> Tyablikov's approximation), but also using the linear spin-wave theory, while some properties<br /> are discussed using the mean-field approximation. The properties which are analyzed in the<br /> thesis are the magnon spectra, magnetization, phase transition temperature, internal energy,<br /> magnon contribution to the specific heat and the magnetic susceptibility. The comparison to<br /> the experimental results suggests the applicability of the Green's function method in the wide<br /> temperature interval from absolute zero to the Néel temperature. We also conclude that it is<br /> justified to consider these compounds as quasi-twodimensional, since it turns out that most<br /> properties do not change significantly when the interplanar exchange is included. On the other<br /> hand, the spin anisotropy parameter, as well as quantum spin fluctuations and short-range<br /> correlations, have great impact on the behaviour of these sytems.</p> | en |
dc.format.mimetype | application/pdf | - |
dc.language.iso | sr (latin script) | - |
dc.publisher | Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu | sr |
dc.publisher | University of Novi Sad, Faculty of Sciences at Novi Sad | en |
dc.source | CRIS UNS | - |
dc.source.uri | http://cris.uns.ac.rs | - |
dc.subject | Hajzenbergov antiferomagnet, kvazi-dvodimenzionalni sistemi, „roditeljska” jedinjenja visokotemperaturskih superprovodnika, metod Grinovih funkcija, magnonski spektri, magnetizacija, magnonska specifična toplota, magnetna susceptibilnost | sr |
dc.subject | Heisenberg antiferromagnet, quasi-twodimensional systems, high-TC “parent” compounds, Green's function method, magnon spectra, magnetization, magnon specific heat, magnetic susceptibility | en |
dc.title | Teorijska istraživanja osobina jako korelisanih kvazi-dvodimenzionalnih nedopiranih kuprata | sr |
dc.title | Theoretical study of the properties of strongly correlated quasi-twodimensional undoped cuprates | en |
dc.type | Thesis | en |
dc.identifier.url | https://www.cris.uns.ac.rs/record.jsf?recordId=81488&source=BEOPEN&language=en | en |
dc.identifier.externalcrisreference | (BISIS)81488 | - |
dc.source.institution | Prirodno-matematički fakultet u Novom Sadu | sr |
item.grantfulltext | none | - |
item.fulltext | No Fulltext | - |
crisitem.author.dept | Prirodno-matematički fakultet, Departman za fiziku | - |
crisitem.author.parentorg | Prirodno-matematički fakultet | - |
Appears in Collections: | PMF Teze/Theses |
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