TY - JOUR
T1 - Synthesis and characterization of (Bi, AE)MnO3 (AE = Ca, Sr) system
AU - Chiba, H.
AU - Atou, T.
AU - Faqir, H.
AU - Kikuchi, M.
AU - Syono, Y.
AU - Murakami, Y.
AU - Shindo, D.
N1 - Funding Information:
We thank T. Mizokawa (Department of Physics, University of Tokyo) for useful discussions. The ICP analysis was performed at Laboratory for Developmental Research of Advanced Materials, the Institute for Materials Research. This research was partially supported by Grant-in-Aid for Scientific Research by the Ministry of Education, Science and Culture, Japan.
PY - 1998/5/1
Y1 - 1998/5/1
N2 - The effects of electron lone pairs of trivalent bismuth ions on the crystal structure and magnetic properties were examined in Bi1-xAExMnO3 (AE = Ca, Sr). Polycrystalline perovskite manganites Bi1-xAExMnO3 were synthesized by using a conventional ceramic technique and a high-pressure technique (4 GPa). Perovskites with triclinic, monoclinic, and tetragonal distortions were found in Bi1-xSrxMnO3 from X-ray powder diffraction. In particular superlattice reflections were found in BiMnO3 by electron diffraction which revealed two kinds of unit cell, i.e. polymorphism. The bismuth lone pair character was reflected in these structures. Both Bi1-xCaxMnO3 and La1-xCaxMnO3 showed the same crystal symmetry and weak ferromagnetism in the Ca-rich region. However, the magnetic moment of Bi1-xCaxMnO3 was larger than that of La1-xCaxMnO3 with the same x value. Their ferromagnetism was suppressed by charge ordering with further substitution of trivalent cations, although the charge ordering temperature of the La-system is higher than that of the Bi system. The difference is probably associated with the Bi lone pair.
AB - The effects of electron lone pairs of trivalent bismuth ions on the crystal structure and magnetic properties were examined in Bi1-xAExMnO3 (AE = Ca, Sr). Polycrystalline perovskite manganites Bi1-xAExMnO3 were synthesized by using a conventional ceramic technique and a high-pressure technique (4 GPa). Perovskites with triclinic, monoclinic, and tetragonal distortions were found in Bi1-xSrxMnO3 from X-ray powder diffraction. In particular superlattice reflections were found in BiMnO3 by electron diffraction which revealed two kinds of unit cell, i.e. polymorphism. The bismuth lone pair character was reflected in these structures. Both Bi1-xCaxMnO3 and La1-xCaxMnO3 showed the same crystal symmetry and weak ferromagnetism in the Ca-rich region. However, the magnetic moment of Bi1-xCaxMnO3 was larger than that of La1-xCaxMnO3 with the same x value. Their ferromagnetism was suppressed by charge ordering with further substitution of trivalent cations, although the charge ordering temperature of the La-system is higher than that of the Bi system. The difference is probably associated with the Bi lone pair.
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U2 - 10.1016/s0167-2738(98)00039-3
DO - 10.1016/s0167-2738(98)00039-3
M3 - Article
AN - SCOPUS:0032073941
SN - 0167-2738
VL - 108
SP - 193
EP - 199
JO - Solid State Ionics
JF - Solid State Ionics
IS - 1-4
ER -