Van Vleck paramagnetism in undoped and Lu-doped bulk ceria

Maxim Varenik, Xiao Dong Zhang, Gregory Leitus, Nimrod Yavo, Raanan Carmieli, Ellen Wachtel, Xin Guo, Igor Lubomirsky

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The magnetic properties of undoped, bulk CeO2 are not fully understood. In contrast to nanocrystalline ceria that exhibits paramagnetism attributed to Ce3+ at grain surfaces, bulk ceria is weakly paramagnetic, despite the absence of magnetic ions. In the present work, the magnetic susceptibility of bulk ceria ceramics doped with Lu3+, which has neither spin nor orbital angular momentum, was measured in order to assess the relative contributions of the crystal lattice, residual Ce3+ and oxygen vacancies to the overall bulk magnetization. We observed a magnetic response consisting of two parts: temperature independent (5-300 K) magnetic susceptibility, and Curie-Weiss paramagnetism. The temperature independent susceptibility decreases linearly with Lu content, and becomes diamagnetic at 30 mol% Lu. The Curie-Weiss magnetism visible at low temperatures was identified as resulting from a few ppm of Fe contaminant. However, Fe contamination does not contribute to the temperature independent paramagnetism. No contribution from Ce3+ could be detected. The fact that the magnetization decreases with Lu content, even though the concentration of oxygen vacancies, and the lattice defects associated with them, increases, indicates that neither is coupled to the magnetic field. Weak, temperature-independent paramagnetism in non-metals is usually attributed to a second order, Van Vleck-type magnetization. However, Van Vleck paramagnetism requires that the population of the first excited state be constant within the range of temperatures investigated. We discuss possible modifications of the large band gap electronic structure of undoped ceria which could account for our observations.

Original languageEnglish
Pages (from-to)27019-27024
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume20
Issue number42
DOIs
Publication statusPublished - Jan 1 2018

Fingerprint

Paramagnetism
paramagnetism
Cerium compounds
Magnetization
magnetic permeability
magnetization
Oxygen vacancies
Magnetic susceptibility
Temperature
temperature
oxygen
crystal lattices
Crystal defects
Angular momentum
Magnetism
contaminants
Excited states
contamination
Crystal lattices
angular momentum

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Varenik, M., Zhang, X. D., Leitus, G., Yavo, N., Carmieli, R., Wachtel, E., ... Lubomirsky, I. (2018). Van Vleck paramagnetism in undoped and Lu-doped bulk ceria. Physical Chemistry Chemical Physics, 20(42), 27019-27024. https://doi.org/10.1039/c8cp04953j

Van Vleck paramagnetism in undoped and Lu-doped bulk ceria. / Varenik, Maxim; Zhang, Xiao Dong; Leitus, Gregory; Yavo, Nimrod; Carmieli, Raanan; Wachtel, Ellen; Guo, Xin; Lubomirsky, Igor.

In: Physical Chemistry Chemical Physics, Vol. 20, No. 42, 01.01.2018, p. 27019-27024.

Research output: Contribution to journalArticle

Varenik, M, Zhang, XD, Leitus, G, Yavo, N, Carmieli, R, Wachtel, E, Guo, X & Lubomirsky, I 2018, 'Van Vleck paramagnetism in undoped and Lu-doped bulk ceria', Physical Chemistry Chemical Physics, vol. 20, no. 42, pp. 27019-27024. https://doi.org/10.1039/c8cp04953j
Varenik M, Zhang XD, Leitus G, Yavo N, Carmieli R, Wachtel E et al. Van Vleck paramagnetism in undoped and Lu-doped bulk ceria. Physical Chemistry Chemical Physics. 2018 Jan 1;20(42):27019-27024. https://doi.org/10.1039/c8cp04953j
Varenik, Maxim ; Zhang, Xiao Dong ; Leitus, Gregory ; Yavo, Nimrod ; Carmieli, Raanan ; Wachtel, Ellen ; Guo, Xin ; Lubomirsky, Igor. / Van Vleck paramagnetism in undoped and Lu-doped bulk ceria. In: Physical Chemistry Chemical Physics. 2018 ; Vol. 20, No. 42. pp. 27019-27024.
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