Structural, transport and spectroscopic properties of Ti⁴⁺ substituted magnetite: Feub>3鈭?span style='font-style: italic'>xub>Tiub>xub>Oub>4ub>

详细信息	查看全文 | 推荐本文 |

• 作者：Dinesh Varshney ; ^{vdinesh33@rediffmail.com} ; ^{vdinesh33@gmail.com} ; Arvind Yogi
• 关键词：74.25.Fy ; 67.80.dk ; 61.05.Qr ; 61.05.cp ; 71.30.+h
• 刊名：Materials Chemistry and Physics
• 出版年：2012
• 期刊代码：58_02540584
• 类别：ms
• 出版时间：15 March, 2012
• 卷：133
• 期：1
• 页码：103-109
• 文件大小：878 K

摘要

The effect of Ti⁴⁺ ion on the formation of magnetite, which were prepared by solid-state route reaction method, were studied by resistivity, Raman and ⁵⁷Fe M枚ssbauer spectrometry. Resistivity measured in the range of 10 < T < 300 K for Ti⁴⁺ magnetite Feub>3鈭?em>xub>Tiub>xub>Oub>4ub> exhibit first order phase transformations at the Verwey transition Tub>vub> for Feub>3ub>Oub>4ub>, Feub>2.98ub>Tiub>0.02ub>Oub>4ub> and Feub>2.97ub>Tiub>0.03ub>Oub>4ub> at 123 K, 121 K and 118 K, respectively. No first order phase transition was observed for Feub>2.9ub>Tiub>0.1ub>Oub>4ub> and small polaron model retraces the semiconducting resistivity behavior with activation energy of about 72 meV. The changes in Raman spectra as a function of doping show that the changes are gradual for samples with higher Ti doping. The Raman active mode for Feub>2.9ub>Tiub>0.1ub>Oub>4ub> at 鈮?34.4 cm^鈭? is shifted as compared to parent Feub>3ub>Oub>4ub> at 鈮?70 cm^鈭?, inferring that Mn²⁺ ions are located mostly on the octahedral sites. ⁵⁷Fe M枚ssbauer spectroscopy probes the site preference of the substitutions and their effect on the hyperfine magnetic fields confirms that Ti⁴⁺ ions are located mostly on the octahedral sites of the Feub>3鈭?em>xub>Tiub>xub>Oub>4ub> spinel structure.