Details

Autor(en) / Beteiligte

• Zhuk, N.A.
• Nekipelov, S.V.
• Sivkov, V.N.
• Makeev, B.A.
• Korolev, R.I.
• Belyy, V.A.
• Krzhizhanovskaya, M.G.
• Ignatova, M.M.

Titel

Magnetic susceptibility, XPS and NEXAFS spectroscopy of Ni-doped CaCu3Ti4O12 ceramics

Ist Teil von

• Materials chemistry and physics, 2020-09, Vol.252, p.123310, Article 123310

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Two series of Ni-doped CaCu3Ti4O12 ceramics with CaCu3Ti4-4хNi4хO12-δ and CaCu3-3хNi3хTi4O12 compositions were obtained by the solid-phase synthesis method. The magnetic behavior of the samples in the range of 77–400 K was studied by magnetic dilution. For the first time the samples of both series were characterized by the spectroscopic methods: XPS and NEXAFS. As a result of XPS spectroscopy, it was found that calcium, copper and nickel atoms mainly have the oxidation state (II), and titanium atoms can exhibit oxidation states of (III) and (IV). NEXAFS-study of Ni-doped CCTO showed that titanium atoms mainly have the oxidation state (IV). In the NEXAFS spectra of nickel of the both series of the samples, a feature associated with the presence of Ni(II) in the square-planar environment was manifested. It was concluded that nickel atoms were distributed in the positions of copper and titanium in the samples of both series. The magnetic behavior of the nickel-doped solid solutions of both types of substitution was different only at x ≥ 0.03, which indicated the advantage of placing nickel (II) atoms in the Cu(II) position. According to the magnetic dilution data, the antiferromagnetic exchange was realized between the nearest paramagnetic nickel atoms in CaCu3Ti4-4хNi4хO12-δ and the ferromagnetic one between the paramagnetic clusters. [Display omitted] •CaCu3Ti4-4хNi4хO12-δ and CaCu3-3хNi3хTi4O12 were synthesized by the solid-state method.•NEXAFS spectra of atoms in Ni-doped CCTO were analyzed for the first time.•The feature of NEXAFS-Ni2p-spectra was Identified.•Antiferromagnetic exchange occurs between the nearest nickel atoms and ferromagnetic exchange occurs between clusters.