Enhanced bulk modulus and reduced transition pressure in gamma-Fe2O3 nanocrystals.

Jianzhong Jiang, J. Staun Olsen, Leif Gerward, Steen Mørup

Research output: Contribution to journalJournal articleResearchpeer-review


Synchrotron radiation X-ray diffraction studies of gamma-Fe2O3 have been performed with emphasis on the pressure-induced phase transformation gamma(maghemite) - alpha(hematite) and the equation of state of the nanophase material. For gamma-Fe2O3 the bulk modulus has been found to increase from 203 GPa for the bulk material to 305 GPa for 9 nm size crystals. At the same time the transition pressure decreases from 35 to 27 GPa. The reduced transition pressure is explained in terms of nucleation and growth, the larger volume change upon transition in the nanocrystalline material being the main factor.
Original languageEnglish
Issue number5
Pages (from-to)620-626
Publication statusPublished - 1998

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