Electrical properties of ferroelectric 1,4-diaminobutane zinc formate crystals under high hydrostatic pressure.*

1,4-diaminobutane zinc formate is an example of metal organic frameworks, MOF, which possesses a nicolite-type structure. This compound is characterized by ordered pore structure, formed by a specific arrangement of atoms formed by coordinating bonds between zinc atoms and formate ligands. Due to its multiferroic properties this compound as well as other MOFs can be applied in memory components.
The electric impedance was measured by means of broadband dielectric spectroscopy (BDS). In the studied crystal one relaxation process was observed. At ambient pressure the phase transition was registered at T = 243 K. The application of Havriliak-Negami model in the description of the relaxation process allowed us to determine relaxation time and consequently activation energy as E_a = 0.48 eV.
The hydrostatic pressure affected both the temperature of phase transition and the relaxation process times. After the sample being pressurized up to 1.7 GPa the phase transition temperature increased by ~ 12 K. Simultaneously the relaxation times got longer which was accompanied by the increase of energy barrier.