Conduction mechanisms in the magnetic insulator [(CH₃)₂NH₂]₂CoCl₄

Abstract

Magnetic susceptibility in the temperature range 170–370 K and ac permittivity and conductivity in the frequency range 5 Hz–1 kHz over the same temperature range for the compound [(CH₃)₂NH₂]₂CoCl₄ were carried out. The results indicate three phase transitions at Tc ₁ = 245 ± 3 K, Tc ₂ = 290 ± 5 K and Tc ₃ = 320 ± 6 K. At T ≥ 290 K the paramagnetic compound conducts via band type mechanism with band gap = 2.42 eV. At lower temperatures correlated barrier hopping mechanism prevails, with an activation energy = 0.52 ± 0.04 eV, an effective barrier height = 0.73 eV and a hopping distance = 36.5 Å.

Keywords:

• Conduction mechanism
• Dielectric properties
• Phase transitions