High-temperature ferromagnetism of Ni-doped PbPdO₂ nanograin films synthesized by sol-gel spin-coating method

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• 作者：C. Mei^a ; J. Liu^a ; P.Y. Chuang^b ; T.T. Song^a ; F.L. Tang^a ; H.L. Su^a ; ^{hailinsu@hfut.edu.cn} ; J.C.A. Huang^b ; ^c ; ^{jcahuang@mail.ncku.edu.tw} ; Y.C. Wu^a ; ^{ycwu@hfut.edu.cn}
• 关键词：Ni-doped PbPdO2 ; Nanograin film ; High-temperature ferromagnetism ; Pb vacancy
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：43
• 期：2
• 页码：1997-2003
• 全文大小：2112 K
• 卷排序：43

文摘

The single-phase Ni-doped PbPdO2 films with a body-centered orthorhombic structure were synthesized by the sol-gel spin-coating method and an oxidation treatment. The films with a thickness of about 440 nm were found to have a nanograin structure and large amount of Pb vacancies. The valence states of Ni and Pd ions within the Ni-doped PbPdO2 films were very close to 2+, while the Pb ions exhibited a mixed valence between 2+ and 4+. The existence of Pb vacancies and the low electronegativity of Pb2+ ion resulted in the increase of the valence of Pb ions. The analysis of the magnetic properties indicated that the magnetisms of the single-phase Ni-doped PbPdO2 nanograin films were all composed of the ferromagnetism and the paramagnetism. The ferromagnetism enhanced with the calcination temperature increasing and could be retained up to 380 K. A carrier-mediated mechanism bridged to the bound magnetic polaron model based on the Pb vacancies, the doped Ni ions and the Pb ions with a valence higher than 2+ were used to explain the magnetic origin of these Ni-doped PbPdO2 nanograin films.