Role of oxygen vacancies in the magnetic and dielectric properties of the high-dielectric-constant system CaCu3 Ti4 O12: An electron-spin resonance study

M. A. Pires, C. Israel, W. Iwamoto, R. R. Urbano, O. Agüero, I. Torriani, C. Rettori, P. G. Pagliuso, L. Walmsley, Z. Le, Joshua Cohn, S. B. Oseroff

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

We report experiments of electron spin resonance (ESR) of Cu2+ in polycrystalline samples of CaCu3 Ti4 O12 post-annealed in different atmospheres. After being synthesized by solid state reaction, pellets of CaCu3 Ti4 O12 were annealed for 24 h at 1000°C under air, Ar or O2. Our temperature dependent ESR data revealed for all samples nearly temperature independent g value (2.15(1)) and linewidth for T TN ≈25 K. However, the values of ESR linewidth are strongly affected by the oxygen content in the sample. For instance, argon post-annealed samples show a much larger linewidth than the O2 or air post-annealed samples. We attribute this broadening to an increase of the dipolar homogeneous broadening of the Cu2+ ESR lines due to the presence of oxygen vacancies which induce an S=1 2 spin inside the TiO6 octahedra. Correlation between a systematic dependence of the ESR linewidth on the oxygen content and the high dielectric constant of these materials is addressed. Also, ESR, magnetic susceptibility, and specific heat data for a single crystal of CaCu3 Ti4 O12 and for polycrystals of CdCu3 Ti4 O12 are reported.

Original languageEnglish (US)
Article number224404
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume73
Issue number22
DOIs
StatePublished - 2006

Fingerprint

Oxygen vacancies
Dielectric properties
Paramagnetic resonance
dielectric properties
Magnetic properties
electron paramagnetic resonance
Permittivity
permittivity
magnetic properties
Linewidth
oxygen
Oxygen
Argon
air
Polycrystals
polycrystals
Air
Solid state reactions
Magnetic susceptibility
resonance lines

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Role of oxygen vacancies in the magnetic and dielectric properties of the high-dielectric-constant system CaCu3 Ti4 O12 : An electron-spin resonance study. / Pires, M. A.; Israel, C.; Iwamoto, W.; Urbano, R. R.; Agüero, O.; Torriani, I.; Rettori, C.; Pagliuso, P. G.; Walmsley, L.; Le, Z.; Cohn, Joshua; Oseroff, S. B.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 73, No. 22, 224404, 2006.

Research output: Contribution to journalArticle

Pires, M. A. ; Israel, C. ; Iwamoto, W. ; Urbano, R. R. ; Agüero, O. ; Torriani, I. ; Rettori, C. ; Pagliuso, P. G. ; Walmsley, L. ; Le, Z. ; Cohn, Joshua ; Oseroff, S. B. / Role of oxygen vacancies in the magnetic and dielectric properties of the high-dielectric-constant system CaCu3 Ti4 O12 : An electron-spin resonance study. In: Physical Review B - Condensed Matter and Materials Physics. 2006 ; Vol. 73, No. 22.
@article{ecc7c92c9bfc43b9acf0ea8f50b21023,
title = "Role of oxygen vacancies in the magnetic and dielectric properties of the high-dielectric-constant system CaCu3 Ti4 O12: An electron-spin resonance study",
abstract = "We report experiments of electron spin resonance (ESR) of Cu2+ in polycrystalline samples of CaCu3 Ti4 O12 post-annealed in different atmospheres. After being synthesized by solid state reaction, pellets of CaCu3 Ti4 O12 were annealed for 24 h at 1000°C under air, Ar or O2. Our temperature dependent ESR data revealed for all samples nearly temperature independent g value (2.15(1)) and linewidth for T TN ≈25 K. However, the values of ESR linewidth are strongly affected by the oxygen content in the sample. For instance, argon post-annealed samples show a much larger linewidth than the O2 or air post-annealed samples. We attribute this broadening to an increase of the dipolar homogeneous broadening of the Cu2+ ESR lines due to the presence of oxygen vacancies which induce an S=1 2 spin inside the TiO6 octahedra. Correlation between a systematic dependence of the ESR linewidth on the oxygen content and the high dielectric constant of these materials is addressed. Also, ESR, magnetic susceptibility, and specific heat data for a single crystal of CaCu3 Ti4 O12 and for polycrystals of CdCu3 Ti4 O12 are reported.",
author = "Pires, {M. A.} and C. Israel and W. Iwamoto and Urbano, {R. R.} and O. Ag{\"u}ero and I. Torriani and C. Rettori and Pagliuso, {P. G.} and L. Walmsley and Z. Le and Joshua Cohn and Oseroff, {S. B.}",
year = "2006",
doi = "10.1103/PhysRevB.73.224404",
language = "English (US)",
volume = "73",
journal = "Physical Review B-Condensed Matter",
issn = "1098-0121",
publisher = "American Institute of Physics Publising LLC",
number = "22",

}

TY - JOUR

T1 - Role of oxygen vacancies in the magnetic and dielectric properties of the high-dielectric-constant system CaCu3 Ti4 O12

T2 - An electron-spin resonance study

AU - Pires, M. A.

AU - Israel, C.

AU - Iwamoto, W.

AU - Urbano, R. R.

AU - Agüero, O.

AU - Torriani, I.

AU - Rettori, C.

AU - Pagliuso, P. G.

AU - Walmsley, L.

AU - Le, Z.

AU - Cohn, Joshua

AU - Oseroff, S. B.

PY - 2006

Y1 - 2006

N2 - We report experiments of electron spin resonance (ESR) of Cu2+ in polycrystalline samples of CaCu3 Ti4 O12 post-annealed in different atmospheres. After being synthesized by solid state reaction, pellets of CaCu3 Ti4 O12 were annealed for 24 h at 1000°C under air, Ar or O2. Our temperature dependent ESR data revealed for all samples nearly temperature independent g value (2.15(1)) and linewidth for T TN ≈25 K. However, the values of ESR linewidth are strongly affected by the oxygen content in the sample. For instance, argon post-annealed samples show a much larger linewidth than the O2 or air post-annealed samples. We attribute this broadening to an increase of the dipolar homogeneous broadening of the Cu2+ ESR lines due to the presence of oxygen vacancies which induce an S=1 2 spin inside the TiO6 octahedra. Correlation between a systematic dependence of the ESR linewidth on the oxygen content and the high dielectric constant of these materials is addressed. Also, ESR, magnetic susceptibility, and specific heat data for a single crystal of CaCu3 Ti4 O12 and for polycrystals of CdCu3 Ti4 O12 are reported.

AB - We report experiments of electron spin resonance (ESR) of Cu2+ in polycrystalline samples of CaCu3 Ti4 O12 post-annealed in different atmospheres. After being synthesized by solid state reaction, pellets of CaCu3 Ti4 O12 were annealed for 24 h at 1000°C under air, Ar or O2. Our temperature dependent ESR data revealed for all samples nearly temperature independent g value (2.15(1)) and linewidth for T TN ≈25 K. However, the values of ESR linewidth are strongly affected by the oxygen content in the sample. For instance, argon post-annealed samples show a much larger linewidth than the O2 or air post-annealed samples. We attribute this broadening to an increase of the dipolar homogeneous broadening of the Cu2+ ESR lines due to the presence of oxygen vacancies which induce an S=1 2 spin inside the TiO6 octahedra. Correlation between a systematic dependence of the ESR linewidth on the oxygen content and the high dielectric constant of these materials is addressed. Also, ESR, magnetic susceptibility, and specific heat data for a single crystal of CaCu3 Ti4 O12 and for polycrystals of CdCu3 Ti4 O12 are reported.

UR - http://www.scopus.com/inward/record.url?scp=33744726525&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33744726525&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.73.224404

DO - 10.1103/PhysRevB.73.224404

M3 - Article

AN - SCOPUS:33744726525

VL - 73

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 22

M1 - 224404

ER -