Effect of the Mn ion on electrical and magnetic properties of orthorhombic perovskite-type Ca(Mn1−xTix)O3−δ |
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Authors: | Katsuyuki Nakade Masaki Kato |
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Affiliation: | a Kyoto Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, JST, 1-7 Hikari-dai, Seika-cho Soraku-gun, Kyoto 619-0237, Japan b Faculty of Engineering, Doshisha University, Kyo-tanabe, Kyoto 610-0321, Japan c Research Laboratory for Surface Science, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan |
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Abstract: | Orthorhombic perovskite-type Ca(Mn1−xTix)O3−δ (0 ≤ x ≤ 0.7) was synthesized at 1173 K for 12 h in a flow of oxygen from a precursor gel prepared using citric acid and ethylene glycol. The Mn3+ ion was generated by substituting a Ti4+ ion in CaMnO3. The average particle size was 100-300 nm and did not depend on x. The lattice constants and the (Mn, Ti)-O distance increased linearly with increasing x. The variation in global instability index (GII) indicated that the instability of the structure increases monotonically with increasing x. Ca(Mn1−xTix)O3−δ was an n-type semiconductor that had its minimum values of electrical resistivity (ρ) and activation energy (Ea) at x = 0.1. Ca(Mn1−xTix)O3−δ (x = 0 and 0.1) exhibited a weak ferromagnetic behavior. The variation in μeff indicated that the spin state of the Mn3+ ion changes from low to high at x = 0.1, then reverts to low in the range of 0.2 ≤ x ≤ 0.7. The variations in ρ and Ea are explained by the number of electrons according to the change in the spin state of the Mn3+ ion. |
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Keywords: | A Oxides B Sol-gel chemistry C X-ray diffraction D Crystal structure D Electrical properties D Magnetic properties |
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