Profiles of oxygen and titanium point defects in ferromagnetic TiO2 films

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F24%3A00584888" target="_blank" >RIV/68081723:_____/24:00584888 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/24:00135763

Výsledek na webu

<a href="https://iopscience.iop.org/article/10.1088/1361-6463/ad3767" target="_blank" >https://iopscience.iop.org/article/10.1088/1361-6463/ad3767</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1361-6463/ad3767" target="_blank" >10.1088/1361-6463/ad3767</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Profiles of oxygen and titanium point defects in ferromagnetic TiO2 films

Popis výsledku v původním jazyce

Experimentally it is shown that without any oxygen manipulation for TiO2, a strong roomntemperature ferromagnetism could be expected only in ultra-thin films, with the ideal thicknessnbelow 100 nm. Both bulks and nano-powders of TiO2 are diamagnetic, indicating that thensurface and its nano-sublayers play very important roles in tailoring the magnetic properties innthis type of compound. To shed a new light on the defect-related magnetism in the typical casenof anatase TiO2 surfaces, we have performed a series of quantum-mechanical calculations fornTiO2 slabs containing Ti or O vacancies in different distances from the (001) surface. Thenlowest formation energies were obtained for the Ti vacancies in the first sub-surface layer andnthe O vacancies within the surface. The computed magnetic states reflect complicated structuralnrelaxations of atoms influenced by both the surface and vacant atomic positions. O atoms cannotncontribute much to magnetic moment when Ti vacancies are isolated and far from the surface.nTi vacancies in TiO2 are only metastable. The formation energy of Ti interstitials is lower thannfor Ti vacancies since high-temperature annealing, especially with a lot of O2 available thatnwould fill up O-related defects, and as a result, eliminate most of Ti vacancies. Lowerntemperatures, less O2, and shorter exposure times may enable not only partial elimination of Tinvacancies but also can facilitate their diffusion into different states of aggregations. In thenferromagnetic films (i.e. thin films below 100 nm), it looks like that the O atoms are locatedncloser to the Ti vacancies.

Název v anglickém jazyce

Profiles of oxygen and titanium point defects in ferromagnetic TiO2 films

Popis výsledku anglicky

Experimentally it is shown that without any oxygen manipulation for TiO2, a strong roomntemperature ferromagnetism could be expected only in ultra-thin films, with the ideal thicknessnbelow 100 nm. Both bulks and nano-powders of TiO2 are diamagnetic, indicating that thensurface and its nano-sublayers play very important roles in tailoring the magnetic properties innthis type of compound. To shed a new light on the defect-related magnetism in the typical casenof anatase TiO2 surfaces, we have performed a series of quantum-mechanical calculations fornTiO2 slabs containing Ti or O vacancies in different distances from the (001) surface. Thenlowest formation energies were obtained for the Ti vacancies in the first sub-surface layer andnthe O vacancies within the surface. The computed magnetic states reflect complicated structuralnrelaxations of atoms influenced by both the surface and vacant atomic positions. O atoms cannotncontribute much to magnetic moment when Ti vacancies are isolated and far from the surface.nTi vacancies in TiO2 are only metastable. The formation energy of Ti interstitials is lower thannfor Ti vacancies since high-temperature annealing, especially with a lot of O2 available thatnwould fill up O-related defects, and as a result, eliminate most of Ti vacancies. Lowerntemperatures, less O2, and shorter exposure times may enable not only partial elimination of Tinvacancies but also can facilitate their diffusion into different states of aggregations. In thenferromagnetic films (i.e. thin films below 100 nm), it looks like that the O atoms are locatedncloser to the Ti vacancies.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

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

Název periodika

Journal of Physics D-Applied Physics

ISSN

0022-3727

e-ISSN

1361-6463

Svazek periodika

57

Číslo periodika v rámci svazku

26

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

265302

Kód UT WoS článku

001196338000001

EID výsledku v databázi Scopus

2-s2.0-85189824930