Influence of oxygen pressure on the expansion dynamic of Ba-hexaferrite ablation plumes and on the properties of deposited thin films

P Papakonstantinou, M.C. O'Neill, R Atkinson, R Al-Wazzan, T Morrow, IW Salter

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Using the pulsed laser deposition (PLD) technique to prepare Ba, Sr-hexaferrite films from stoichiometric targets, it has been found that the degree of perpendicular anisotropy of the films is sensitive to, among other parameters, the background oxygen ambient. In an effort to better understand the ablated material transport under Ba-hexaferrite film growth conditions, an emission spectroscopy study was initiated. Temporally integrated spectra were collected as a function of distance above the target surface and as a function of oxygen pressure (PO2). Only emission lines from Ba, Fe neutrals and singly ionised Ba species were observed. However, emission features from oxide molecules were not identified even in the presence of oxygen. The plasma appeared highly ionised close to the target and, during its propagation towards the substrate, expanded to a low density weakly ionised vapour, mostly populated with Ba and Fe neutrals. High local equilibrated gas temperatures (of the order of 0.8 eV) in the deposition region are thought to facilitate film crystallisation and oriented growth. The emission signal was found to depend on oxygen pressure and the distance from the target. Generally, it decreased with distance and increased with PO2. It was deduced that the optical emission is excited by electron impact excitation. Moreover, both temporal profiles of the constituent line intensities and time-resolved images of the overall optical plasma emission consistently demonstrated that the oxygen pressure confines the plasma, slows its expansion and enhances the emission particularly at its expanding front. The change observed in the quality of Ba ferrite films with oxygen pressure is discussed in terms of the behaviour of the expanding plume with increasing PO2.
LanguageEnglish
Pages120-129
JournalJournal of Magnetism and Magnetic Materials
Volume189
DOIs
Publication statusPublished - 6 May 1998

Fingerprint

Ablation
ablation
plumes
Oxygen
Thin films
expansion
oxygen
thin films
Plasmas
Emission spectroscopy
Film growth
Pulsed laser deposition
gas temperature
Crystallization
Oxides
electron impact
pulsed laser deposition
light emission
Ferrite
ferrites

Cite this

@article{2bf78814e71542659a474966c20c77bd,
title = "Influence of oxygen pressure on the expansion dynamic of Ba-hexaferrite ablation plumes and on the properties of deposited thin films",
abstract = "Using the pulsed laser deposition (PLD) technique to prepare Ba, Sr-hexaferrite films from stoichiometric targets, it has been found that the degree of perpendicular anisotropy of the films is sensitive to, among other parameters, the background oxygen ambient. In an effort to better understand the ablated material transport under Ba-hexaferrite film growth conditions, an emission spectroscopy study was initiated. Temporally integrated spectra were collected as a function of distance above the target surface and as a function of oxygen pressure (PO2). Only emission lines from Ba, Fe neutrals and singly ionised Ba species were observed. However, emission features from oxide molecules were not identified even in the presence of oxygen. The plasma appeared highly ionised close to the target and, during its propagation towards the substrate, expanded to a low density weakly ionised vapour, mostly populated with Ba and Fe neutrals. High local equilibrated gas temperatures (of the order of 0.8 eV) in the deposition region are thought to facilitate film crystallisation and oriented growth. The emission signal was found to depend on oxygen pressure and the distance from the target. Generally, it decreased with distance and increased with PO2. It was deduced that the optical emission is excited by electron impact excitation. Moreover, both temporal profiles of the constituent line intensities and time-resolved images of the overall optical plasma emission consistently demonstrated that the oxygen pressure confines the plasma, slows its expansion and enhances the emission particularly at its expanding front. The change observed in the quality of Ba ferrite films with oxygen pressure is discussed in terms of the behaviour of the expanding plume with increasing PO2.",
author = "P Papakonstantinou and M.C. O'Neill and R Atkinson and R Al-Wazzan and T Morrow and IW Salter",
year = "1998",
month = "5",
day = "6",
doi = "10.1016/S0304-8853(98)00232-7",
language = "English",
volume = "189",
pages = "120--129",
journal = "Journal of Magnetism and Magnetic Materials",
issn = "0304-8853",
publisher = "Elsevier",

}

Influence of oxygen pressure on the expansion dynamic of Ba-hexaferrite ablation plumes and on the properties of deposited thin films. / Papakonstantinou, P; O'Neill, M.C.; Atkinson, R; Al-Wazzan, R; Morrow, T; Salter, IW.

In: Journal of Magnetism and Magnetic Materials, Vol. 189, 06.05.1998, p. 120-129.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Influence of oxygen pressure on the expansion dynamic of Ba-hexaferrite ablation plumes and on the properties of deposited thin films

AU - Papakonstantinou, P

AU - O'Neill, M.C.

AU - Atkinson, R

AU - Al-Wazzan, R

AU - Morrow, T

AU - Salter, IW

PY - 1998/5/6

Y1 - 1998/5/6

N2 - Using the pulsed laser deposition (PLD) technique to prepare Ba, Sr-hexaferrite films from stoichiometric targets, it has been found that the degree of perpendicular anisotropy of the films is sensitive to, among other parameters, the background oxygen ambient. In an effort to better understand the ablated material transport under Ba-hexaferrite film growth conditions, an emission spectroscopy study was initiated. Temporally integrated spectra were collected as a function of distance above the target surface and as a function of oxygen pressure (PO2). Only emission lines from Ba, Fe neutrals and singly ionised Ba species were observed. However, emission features from oxide molecules were not identified even in the presence of oxygen. The plasma appeared highly ionised close to the target and, during its propagation towards the substrate, expanded to a low density weakly ionised vapour, mostly populated with Ba and Fe neutrals. High local equilibrated gas temperatures (of the order of 0.8 eV) in the deposition region are thought to facilitate film crystallisation and oriented growth. The emission signal was found to depend on oxygen pressure and the distance from the target. Generally, it decreased with distance and increased with PO2. It was deduced that the optical emission is excited by electron impact excitation. Moreover, both temporal profiles of the constituent line intensities and time-resolved images of the overall optical plasma emission consistently demonstrated that the oxygen pressure confines the plasma, slows its expansion and enhances the emission particularly at its expanding front. The change observed in the quality of Ba ferrite films with oxygen pressure is discussed in terms of the behaviour of the expanding plume with increasing PO2.

AB - Using the pulsed laser deposition (PLD) technique to prepare Ba, Sr-hexaferrite films from stoichiometric targets, it has been found that the degree of perpendicular anisotropy of the films is sensitive to, among other parameters, the background oxygen ambient. In an effort to better understand the ablated material transport under Ba-hexaferrite film growth conditions, an emission spectroscopy study was initiated. Temporally integrated spectra were collected as a function of distance above the target surface and as a function of oxygen pressure (PO2). Only emission lines from Ba, Fe neutrals and singly ionised Ba species were observed. However, emission features from oxide molecules were not identified even in the presence of oxygen. The plasma appeared highly ionised close to the target and, during its propagation towards the substrate, expanded to a low density weakly ionised vapour, mostly populated with Ba and Fe neutrals. High local equilibrated gas temperatures (of the order of 0.8 eV) in the deposition region are thought to facilitate film crystallisation and oriented growth. The emission signal was found to depend on oxygen pressure and the distance from the target. Generally, it decreased with distance and increased with PO2. It was deduced that the optical emission is excited by electron impact excitation. Moreover, both temporal profiles of the constituent line intensities and time-resolved images of the overall optical plasma emission consistently demonstrated that the oxygen pressure confines the plasma, slows its expansion and enhances the emission particularly at its expanding front. The change observed in the quality of Ba ferrite films with oxygen pressure is discussed in terms of the behaviour of the expanding plume with increasing PO2.

U2 - 10.1016/S0304-8853(98)00232-7

DO - 10.1016/S0304-8853(98)00232-7

M3 - Article

VL - 189

SP - 120

EP - 129

JO - Journal of Magnetism and Magnetic Materials

T2 - Journal of Magnetism and Magnetic Materials

JF - Journal of Magnetism and Magnetic Materials

SN - 0304-8853

ER -