Ferroelectric structural transition in hafnium oxide induced by charged oxygen vacancies

2021 ◽  
Vol 104 (18) ◽  
Author(s):  
Ri He ◽  
Hongyu Wu ◽  
Shi Liu ◽  
Houfang Liu ◽  
Zhicheng Zhong
Keyword(s):  
Hafnium Oxide ◽  
Oxygen Vacancies ◽  
Structural Transition

Effect of Mn Substitution on Microstructures, Dielectric and Magnetic Properties of BiFeO3 Ceramics

2015 ◽  
Vol 815 ◽  
pp. 188-193
Author(s):  
Xiao Ling Deng ◽  
Wei Cai ◽  
Chun Lin Fu ◽  
Yu Qin Zhang ◽  
Rong Li Gao ◽  
...  
Keyword(s):  
Phase Transition ◽  
Remanent Magnetization ◽  
Oxygen Vacancies ◽  
Structural Transition ◽  
Manganese Content ◽  
Sol Gel ◽  
Structural Phase ◽  
Mn Substitution ◽  
Magnetization Field ◽  
Mn Doped

Pure BiFeO3 ceramics and BiMnxFe1-xO3 (x=0.1, 0.15, 0.2, and 0.25) ceramics were prepared by sol-gel method. A structural phase transition from rhombohedral R3c to triangle R3m occurred in Mn-doped BFO ceramics. Mn-doped BFO ceramics exhibited better crystallinity, larger dielectric constant as well as smaller dielectric loss. Besides, a small nonlinearity of magnetization-field curves M(H) was observed, the remanent magnetization increased with the increase of manganese content, and all the BiMnxFe1-xO3 ceramics showed the typical antiferromagnetic, which could be attributed to the effective decrease in the concentration of oxygen vacancies, and the corresponding structural transition.

scholarly journals Evidence for oxygen vacancies movement during wake-up in ferroelectric hafnium oxide

2016 ◽  
Vol 108 (3) ◽  
pp. 032903 ◽  
Author(s):  
S. Starschich ◽  
S. Menzel ◽  
U. Böttger
Keyword(s):  
Hafnium Oxide ◽  
Oxygen Vacancies

Electronic structure of oxygen vacancies in hafnium oxide

2013 ◽  
Vol 109 ◽  
pp. 21-23 ◽  
Author(s):  
T.V. Perevalov ◽  
V.Sh. Aliev ◽  
V.A. Gritsenko ◽  
A.A. Saraev ◽  
V.V. Kaichev
Keyword(s):  
Electronic Structure ◽  
Hafnium Oxide ◽  
Oxygen Vacancies

Luminescence study of oxygen vacancies in lanthanum hafnium oxide, La2Hf2O7

2013 ◽  
Vol 137 ◽  
pp. 93-97 ◽  
Author(s):  
Yetta Eagleman ◽  
Marvin Weber ◽  
Stephen Derenzo
Keyword(s):  
Hafnium Oxide ◽  
Oxygen Vacancies ◽  
Luminescence Study

The Evolution of the Conductivity and Cathodoluminescence of the Films of Hafnium Oxide in the Case of a Change in the Concentration of Oxygen Vacancies

2018 ◽  
Vol 60 (10) ◽  
pp. 2050-2057 ◽  
Author(s):  
D. R. Islamov ◽  
V. A. Gritsenko ◽  
V. N. Kruchinin ◽  
E. V. Ivanova ◽  
M. V. Zamoryanskaya ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Oxygen Vacancies

scholarly journals Эволюция проводимости и катодолюминесценции пленок оксида гафния при изменении концентрации вакансий кислорода

2018 ◽  
Vol 60 (10) ◽  
pp. 2006
Author(s):  
Д.Р. Исламов ◽  
В.А. Гриценко ◽  
В.Н. Кручинин ◽  
Е.В. Иванова ◽  
М.В. Заморянская ◽  
...  
Keyword(s):  
Refractive Index ◽  
Hafnium Oxide ◽  
Oxygen Vacancies ◽  
Trap Density ◽  
Blue Band ◽  
In Situ Method ◽  
Assisted Tunneling ◽  
Strong Scattering

AbstractThe dependence of the conductivity of the films of hafnium oxide HfO_2 synthesized in different modes is studied. Depending on the modes of synthesis, the conductivity of HfO_2 at a fixed electric field of 1.0 MV/cm changes by four orders of magnitude. It is found that the conductivity of HfO_2 is limited by the model of phonon-assisted tunneling between the traps. The thermal and optical energies of the traps W _t = 1.25 eV and W _opt = 2.5 eV, respectively, in HfO_2 are determined. It is found that the exponentially strong scattering of the conductivity of HfO_2 is due to the change in the trap density in a range of 4 × 10^19–2.5 × 10^22 cm^–3. In the cathodoluminescence spectra of HfO_2, a blue band with the energy of 2.7 eV is observed which is due to the oxygen vacancies. A correlation between the trap density and intensity of cathodoluminescence, as well as between the trap density and refractive index, is found. A nondestructive in situ method for the determination of the trap density of hafnium oxide with the use of the measurement of the refractive index is proposed. The optimum values of the concentrations of oxygen vacancies for emitting devices on the basis of the films of HfO_2 are found.

Conditions for atomic imaging of mullite

1989 ◽  
Vol 47 ◽  
pp. 418-419
Author(s):  
T. A. Epicier ◽  
G. Thomas
Keyword(s):  
Oxygen Vacancies ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Work Conditions ◽  
Real Space ◽  
Potential Candidate ◽  
Silicate Mineral ◽  
Resolution Electron ◽  
The Subject ◽  
Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

Sign in / Sign up

Export Citation Format

Share Document