Open AccessBroad-Band Dielectric Spectroscopy Reveals Peak Values of Conductivity and Permittivity Switching upon Spin Crossover
Author(s) -
Ion Soroceanu,
Adrian Graur,
Eugen Coca,
Lionel Salmon,
Gábor Molnár,
Philippe Demont,
Azzedine Bousseksou,
Aurelian Rotaru
Publication year - 2019
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.9b02678
Subject(s) - condensed matter physics , dielectric , permittivity , dielectric spectroscopy , materials science , conductivity , relaxation (psychology) , dipole , relative permittivity , spin polarization , electrical resistivity and conductivity , nuclear magnetic resonance , electrode , chemistry , physics , optoelectronics , psychology , social psychology , organic chemistry , quantum mechanics , electrochemistry , electron
We use broad-band dielectric spectroscopy to investigate the spin-state dependence of electrical properties of the [Fe(Htrz) 2 (trz)](BF 4 ) spin crossover complex. We show that the Havriliak-Negami theory can fully describe the variation of the complex dielectric permittivity of the material across the pressure-temperature phase diagram. The analysis reveals three dielectric relaxation processes, which we attribute to electrode/interface polarization, dipole relaxation, and charge transport relaxation. The contribution of the latter appears significant to the dielectric strength. Remarkably, the permittivity and conductivity changes between the high spin and low spin states are amplified at the corresponding relaxation frequencies.
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