Effect of Grain Size on Pressure-Induced Structural Transition in Mn3O4

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• 作者：Hang Lv ; Mingguang Yao ; Quanjun Li ; Zepeng Li ; Bo Liu ; Ran Liu ; Shuangchen Lu ; Dongmei Li ; Jun Mao ; Xiangling Ji ; Jing Liu ; Zhiqiang Chen ; Bo Zou ; Tian Cui ; Bingbing Liu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 26, 2012
• 年：2012
• 卷：116
• 期：3
• 页码：2165-2171
• 全文大小：977K
• 年卷期：v.116,no.3(January 26, 2012)
• ISSN：1932-7455

文摘

The size effect on structural transitions of Mn₃O₄ has been investigated under pressures by in situ synchrotron X-ray diffraction and Raman technique in a diamond anvil cell. Compared with bulk Mn₃O₄, Mn₃O₄ nanoparticles show an obvious elevation of phase transition pressure and different phase transformation routines with the occurrence of a new high-pressure phase at 14.5鈥?3.5 GPa. The new phase most probably has an orthorhombic CaTi₂O₄-type structure, which is regarded as a metastable phase transforming to the higher pressure marokite-like structure. By the return to ambient pressure, the marokite phase is quenchable in bulk Mn₃O₄, whereas the coexistence of hausmannite and marokite phase is observed in the recovered Mn₃O₄ nanoparticles. It is proposed that the unique atomic conformation in Mn₃O₄ spinel structures, the cation distribution, and the higher surface energy together with the size-induced effect of nanocrystalline Mn₃O₄ probably play crucial roles in the high-pressure behavior of Mn₃O₄ nanoparticles.