Possible room-temperature ferromagnetism in K-doped SnO2: X-ray diffraction and high-resolution transmission electron microscopy study - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2010

Possible room-temperature ferromagnetism in K-doped SnO2: X-ray diffraction and high-resolution transmission electron microscopy study

Résumé

Ab initio studies have theoretically predicted room-temperature ferromagnetism in crystalline SnO2, ZrO2, and TiO2 doped with nonmagnetic element from the 1A column as K and Na. Our purpose is to address experimentally the possibility of magnetism in both Sn1−xKxO2 and Sn1−xCaxO2 compounds. The samples have been prepared using equilibrium methods of standard solid-state route. Our study has shown that both Sn1−xCaxO2 and Sn1−xKxO2 structure is thermodynamically unstable and leads to a phase separation, as shown by x-ray diffraction and detailed microstructural analyses with high-resolution transmission electron microscopy. In particular, the crystalline SnO2 grains are surrounded by K-based phase. In contrast to Ca:SnO2 samples, we have obtained a magnetic phase in K:SnO2 ones but no long-range ferromagnetic order. The K:SnO2 samples exhibit a moment on the order of 0.2 μB/K /ion, in contrast to ab initio calculations which predict 3 μB, where K atoms are on the Sn crystallographic site. The apparent contradictions between our experiments and first-principles studies are discussed.

Dates et versions

hal-01010639 , version 1 (20-06-2014)

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Sandeep Srivastava, Pascal Lejay, Bernard Barbara, S. Pailhes, V. Madigou, et al.. Possible room-temperature ferromagnetism in K-doped SnO2: X-ray diffraction and high-resolution transmission electron microscopy study. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 82 (19), pp.193203. ⟨10.1103/PhysRevB.82.193203⟩. ⟨hal-01010639⟩
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