AC Dielectric and Conductivity Studies of a Perovskite Magnetic Insulator

Self Cite

The AC conductivity in the frequency range 5.0 Hz -10.0 kHz, the magnetic susceptibility in a field of 14.7 and 17.810 4 A/m, and differential thermal analysis at 78 K up to room temperature for bis-(ethanolammonium)Co 2 X 6 ,X = CI and Br are reported. The bromide dimer undergoes an order-disorder transition at 302 K and a displacive type ferroelectric transition at T ~ 220 K. The chloride dimer shows two transitions, the first being in a displacive ferroelectric one at T ~ 210 K showing critical slowing down. The second phase transition, occuring at 282 K, is found to be inactive in the electric measurements.

Section: Magnetic Susceptibility Resultssupporting

confidence: 81%

Dielectric Dispersion of New Ferroelectric Cobalt Halide Dimers: Bis-ethanolammonium-hexahalocobaltate, (C 2 H 8 NO) 2 Co 2 X 6 , X = CI/Br

Mostafa

Arafat

2000

Self Cite

“…The sample was prepared as described in [14]. The yellow sample of [(CH 2 ) 3 (NH 3 ) 2 ]CuCl 4 , denoted C3Cu, was recrystallized from a mixture of alcohol and diethyl ether and then dried in vacuum.…”

Section: Methodsmentioning

confidence: 99%

The Frequency Dependence of the Conductivity and Dielectric Relaxation of [(CH₂)₃(NH₃)₂]Cu(II)Cl₄

Mostafa

Youssef

Montasser

et al. 2005

The structural, dielectric and conductive properties of [(CH 2 ) 3 (NH 3 ) 2 ]Cu(II)Cl 4 have been studied. The material shows an order-disorder transition at T 1 = (333 ± 2) K and a ferroelectric phase transitions at T 2 = (434 ± 3) K. Results of differential thermal analysis, infrared spectroscopy, X-ray diffraction, AC conductivity and permittivity measurements are reported and discussed. The conductivity results are interpreted in terms of barrier hopping at low and intermediate temperatures, and band-type conduction at high temperatures. -PACS: 81.05.-t, 77.22.-d

“…Most previously studied isomorphous perovskite materials in our laboratory [3,[11][12][13] and elsewhere [15,16], were found to follow a universal power law…”

Section: Conductivity A) Frequency Dependent Conductivitymentioning

confidence: 99%

“…The measuring technique is discussed in [13]. The pellets were coated with silver paste to ensure good electrical contact.…”

Section: Electric Measurementsmentioning

confidence: 99%

The Permittivity and AC Conductivity of the Layered Perovskite [(CH₃)(C₆H₅)₃P]₂HgI₄

Youssef

2002

The dielectric permittivity and ac conductivity of bis-(Methyltriphenyl-phosphonium) 2 tetraiodomercurate (II), [(CH 3 )(C 6 H 5 ) 3 P] 2 HgI 4 , has been measured in at 300-400 K and 0.11-20 kHz. The frequency dependent conductivity is interpreted in terms of the jump relaxation model, where translational and reorientational hopping takes place. The conductivity results were fitted to the law, with s < 1 and r < 2 .The temperature dependence of the conductivity was fitted to two relaxation processes. * first order, ** second order.