Heat capacity and magnetic phase transition of two-dimensional metal-assembled complex (NEt4)[{MnIII(salen)} 2FeIII(CN)6]

Y. Miyazaki, T. Sakakibara, H. Miyasaka, N. Matsumoto, M. Sorai

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Heat capacity measurements of the two-dimensional metal-assembled complex, (NEt4)[{MnIII(salen)}2FeIII(CN) 6] [Et=ethyl, salen= N,N'-ethylenebis(salicylideneaminato) dianion], were performed in the temperature range between 0.2 and 300 K by adiabatic calorimetry. A ferrimagnetic phase transition was observed at T c1=7.51 K. Furthermore, another small magnetic phase transition appeared at T c2=0.78 K. Above T c1, a heat capacity tail arising from the short-range ordering of the spins characteristic of two-dimensional magnets was found. The magnetic enthalpy and entropy were evaluated to be ΔH=291 J mol-1 and ΔS=27.4 J K -1 mol-1, respectively. The experimental magnetic entropy agrees roughly with ΔS=Rln(5•5•2) (=32.5 J K-1 mol-1; R being the gas constant), which is expected for the metal complex with two Mn(III) ions in high-spin state (spin quantum number S=2) and one Fe(III) ion in low-spin state (S=1/2). The heat capacity tail above T c1 became small by grinding and pressing the crystal. This mechanochemical effect would be attributed to the increase of lattice defects and imperfections in the crystal lattice, leading not only to formation of the crystal with a different magnetic phase transition temperature but also to decrease of the magnetic heat capacity and thus the magnetic enthalpy and entropy.

Original languageEnglish
Pages (from-to)603-607
Number of pages5
JournalJournal of Thermal Analysis and Calorimetry
Volume81
Issue number3
DOIs
Publication statusPublished - 2005 Aug
Externally publishedYes

Keywords

  • Heat capacity
  • Magnetic phase transition
  • Mechanochemical effect
  • Metal-assembled complex

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Heat capacity and magnetic phase transition of two-dimensional metal-assembled complex (NEt<sub>4</sub>)[{Mn<sup>III</sup>(salen)} <sub>2</sub>Fe<sup>III</sup>(CN)<sub>6</sub>]'. Together they form a unique fingerprint.

Cite this