Mössbauer investigation of 57Fe-doped Ni(III) perovskites ANi0.98Fe0.02O3 (A = Pr, Nd, Sm, Y, Lu, Tl) versus temperature

Seung-Joo Kim (1) , Igor Presniakov (2) , Gérard Demazeau (1) , Konstantin Pokholok (2) , Alexey Baranov (2) , Alexey Sobolev (2) , Denis Pankratov (2) , Nikolay S. Ovanesyan (3)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Chair of Radiochemistry, Department of Chemistry
3 Institute of Problems of Chemical Physics

Nickelates ANiO3 (A=Pr, Nd, Sm, Lu, Y, Tl) containing Mössbauer probe 57Fe atoms were synthesized. In the case of nickelates with larger rare earth (A=Pr, Nd, Sm) the Mössbauer spectra confirm that ferric ions are located in single type of crystallographic positions. On the contrary, the spectra of ANi0.98Fe0.02O3 with small cations (A=Lu, Y, Tl) can be described as a superposition of two sub-spectra which indicate that 57Fe probe atoms are simultaneously stabilized in two non-equivalent crystallographic positions. These results have been interpreted in terms of partial charge disproportionation of Ni3+ cations associated with the electronic localization in monoclinic distorted Lu, Y, Tl nickelates. The modification of 57Fe spectra for TlNi0.98Fe0.02O3 as a function of temperature has shown that this charge disproportionation occurs in varying degrees, corresponding to the charge states Fe(3+σ)+ and Fe(3−σ′)+. On the contrary, the spectra for Lu and Y nickelates show that charge variation (σ,σ′) for dopant Fe(1) and Fe(2) cations does not depend on temperature.

Mots clés: Mössbauer spectroscopy; Perovskite; Trivalent nickel; Charge disproportionation

Domaines: Matériaux

Seung-Joo Kim, Igor Presniakov, Gérard Demazeau, Konstantin Pokholok, Alexey Baranov, et al.. Mössbauer investigation of 57Fe-doped Ni(III) perovskites ANi0.98Fe0.02O3 (A = Pr, Nd, Sm, Y, Lu, Tl) versus temperature. Journal of Solid State Chemistry, 2002, 168 (1), pp.126-133. ⟨10.1006/jssc.2002.9699⟩. ⟨hal-00817239⟩