Vacancy-induced magnetism in TiO2 thin films

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F23%3A00133889" target="_blank" >RIV/00216224:14310/23:00133889 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Vacancy-induced magnetism in TiO2 thin films

Popis výsledku v původním jazyce

We present a combined experimental and theoretical study of surface-related magnetic states in TiO2. Our experiments performed on nano-sized thin films of pure TiO2 have suggested that the observed room-temperature magnetism originates from defects, particularly from the surface of thin films as well as from point defects, such as vacancies located mainly at the surface. To clarify this phenomenon, we performed quantum-mechanical density functional theory (DFT) calculations. Our fixed-spin-moment calculations identified both the bulk and the bulk-like TiO2-terminated vacancy-free (001) surfaces as non-magnetic. In contrast, oxygen vacancies in the TiO-terminated and TiO0.75-terminated (001) surfaces led to ferromagnetic and rather complex ferrimagnetic states, respectively. The spin-polarized atoms are the Ti atoms (due to the d-states) located in the surface and sub-surface atomic planes. Finally, the O-terminated surfaces are also magnetic due to the surface and sub-surface oxygen atoms and sub-surface Ti atoms (however, their surface energy is high). For further details, see Friák et al., Journal of Applied Physics 134, 013902 (2023), DOI: 10.1063/5.0155282.

Název v anglickém jazyce

Vacancy-induced magnetism in TiO2 thin films

Popis výsledku anglicky

We present a combined experimental and theoretical study of surface-related magnetic states in TiO2. Our experiments performed on nano-sized thin films of pure TiO2 have suggested that the observed room-temperature magnetism originates from defects, particularly from the surface of thin films as well as from point defects, such as vacancies located mainly at the surface. To clarify this phenomenon, we performed quantum-mechanical density functional theory (DFT) calculations. Our fixed-spin-moment calculations identified both the bulk and the bulk-like TiO2-terminated vacancy-free (001) surfaces as non-magnetic. In contrast, oxygen vacancies in the TiO-terminated and TiO0.75-terminated (001) surfaces led to ferromagnetic and rather complex ferrimagnetic states, respectively. The spin-polarized atoms are the Ti atoms (due to the d-states) located in the surface and sub-surface atomic planes. Finally, the O-terminated surfaces are also magnetic due to the surface and sub-surface oxygen atoms and sub-surface Ti atoms (however, their surface energy is high). For further details, see Friák et al., Journal of Applied Physics 134, 013902 (2023), DOI: 10.1063/5.0155282.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA22-21547S" target="_blank" >GA22-21547S: Původ feromagnetismu při pokojové teplotě v tenkých vrstvách nedopovaných polovodičových oxidů typu d0</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů