Magdi Mohamed Mashly

The dielectric constant ε′ as well as the dielectric loss tan δ on a pellet of powdered (CH2)8(NH3)2MCl4 (M = Mn and Fe) are measured as a function of temperature. ε′ and tan δ reveal more than one peak. One of these peaks is due to a structural phase transition and the others are due to order-disorder and chain melting transitions. Electronic, ionic, and rotational polarization are taken into consideration.

The dielectric constant ε′ as well as the dielectric loss tan δ on a pellet of powdered (CH2)8(NH3)2MCl4 (M = Mn and Fe) are measured as a function of temperature. ε′ and tan δ reveal more than one peak. One of these peaks is due to a structural phase transition and the others are due to order-disorder and chain melting transitions. Electronic, ionic, and rotational polarization are taken into consideration.

The dielectric constants of benzaldazine (BA) and its nitro derivatives have been measured at different frequencies up to 200 kHz. The measurements were carried out at temperatures up to and near the melting point of each sample. Two phase transitions were obtained during measurements at 310 and 480 K. Inversion NN rotation and inversion CN rotation mechanisms may be responsible for these transitions. The effect of interaction between the strongly polar NO2 group of o-, m- or p-nitrobenzaldazine and the central aldimino (CHN) groups on the dielectric constant is discussed. The electric dipole moments of the samples were calculated at the peak positions, and are discussed. © 1995.

The dielectric constants of benzaldazine (BA) and its nitro derivatives have been measured at different frequencies up to 200 kHz. The measurements were carried out at temperatures up to and near the melting point of each sample. Two phase transitions were obtained during measurements at 310 and 480 K. Inversion NN rotation and inversion CN rotation mechanisms may be responsible for these transitions. The effect of interaction between the strongly polar NO2 group of o-, m- or p-nitrobenzaldazine and the central aldimino (CHN) groups on the dielectric constant is discussed. The electric dipole moments of the samples were calculated at the peak positions, and are discussed. © 1995.

The thermally stimulated current (TSC) has been measured for diaminooctane-FeCd tetrachloride compounds in the temperature range that includes their phase transition points. The dilution of the metallic layers by non-magnetic Cd ions (15, 27, 40, 50, 60, 70 and 80 mol%) decreases the TSC until the critical concentration (≈50 mol%) is reached, then it increases again. © 1995.

The thermally stimulated current (TSC) has been measured for diaminooctane-FeCd tetrachloride compounds in the temperature range that includes their phase transition points. The dilution of the metallic layers by non-magnetic Cd ions (15, 27, 40, 50, 60, 70 and 80 mol%) decreases the TSC until the critical concentration (≈50 mol%) is reached, then it increases again. © 1995.