Faculté des sciences

DC magnetization investigations in Ti1−xMnxO₂ nanocrystalline powder

Sharma, Sudesh ; Chaudhary, Sujeet ; Kashyap, Subhash C. ; Malik, Vivek K.

In: Journal of Alloys and Compounds, 2011, vol. 509, no. 27, p. 7434-7438

In the present paper, DC magnetization investigation on the insulating nanocrystalline powder samples of Ti1−xMnxO₂ (x = 0, 0.05, 0.10, and 0.15) prepared by simple chemical route is reported. Structural measurements revealed phase pure anatase structure of TiO₂ when x ≤ 0.05 and a mixture of anatase and rutile TiO₂ along with the... Plus

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    Summary
    In the present paper, DC magnetization investigation on the insulating nanocrystalline powder samples of Ti1−xMnxO₂ (x = 0, 0.05, 0.10, and 0.15) prepared by simple chemical route is reported. Structural measurements revealed phase pure anatase structure of TiO₂ when x ≤ 0.05 and a mixture of anatase and rutile TiO₂ along with the signature of Mn₃O₄ phase for x > 0.05. Magnetic measurements exhibited the presence of ferromagnetic ordering at room temperature in samples having either small fraction of Mn or no Mn at all. This ferromagnetic signature is accompanied with paramagnetic contribution which is found to dominate with increase in Mn concentration. The Ti1−xMnxO₂ sample having highest Mn concentration of x = 0.15 showed nearly paramagnetic behavior. However, at low temperatures, additional ferrimagnetic ordering arising due to Mn₃O₄ (TC = 42 K) is evidenced in the doped samples. Consistent with the XRD investigations, the isofield DC-magnetization measurements under field cooled and zero field cooled (FC–ZFC) histories corroborated the presence of Mn₃O₄ phase. Also, distinct thermomagnetic irreversibility has been observed above 42 K. These results are suggestive of presence of weak ferromagnetic ordering possibly due to defects related with oxygen vacancies.