Experimental heat capacities, excess entropies, and magnetic properties of bulk and nano Fe3O4-Co3O4 and Fe3O4-Mn3O4 spinel solid solutions

Jacob M. Schliesser, Baiyu Huang, Sulata K. Sahu, Megan Asplund, Alexandra Navrotsky, Brian F. Woodfield

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We have measured the heat capacities of several well-characterized bulk and nanophase Fe3O4-Co3O4 and Fe3O4-Mn3O4 spinel solid solution samples from which magnetic properties of transitions and third-law entropies have been determined. The magnetic transitions show several features common to effects of particle and magnetic domain sizes. From the standard molar entropies, excess entropies of mixing have been generated for these solid solutions and compared with configurational entropies determined previously by assuming appropriate cation and valence distributions. The vibrational and magnetic excess entropies for bulk materials are comparable in magnitude to the respective configurational entropies indicating that excess entropies of mixing must be included when analyzing entropies of mixing. The excess entropies for nanophase materials are even larger than the configurational entropies. Changes in valence, cation distribution, bonding and microstructure between the mixing ions are the likely sources of the positive excess entropies of mixing.

Original languageEnglish (US)
Pages (from-to)79-90
Number of pages12
JournalJournal of Solid State Chemistry
Volume259
DOIs
StatePublished - Mar 2018
Externally publishedYes

Keywords

  • Entropy of mixing
  • Heat capacity
  • Nanoparticle
  • Spinel solid solutions

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'Experimental heat capacities, excess entropies, and magnetic properties of bulk and nano Fe<sub>3</sub>O<sub>4</sub>-Co<sub>3</sub>O<sub>4</sub> and Fe<sub>3</sub>O<sub>4</sub>-Mn<sub>3</sub>O<sub>4</sub> spinel solid solutions'. Together they form a unique fingerprint.

Cite this