Polarization Reversal and Switching in Guanidinium Aluminum Sulfate Hexahydrate Single Crystals

The ferroelectric switching properties of GASH (CN3H6).Al(SO4)2.6H2O were studied under sinewave and pulse conditions. The results indicate that the polarization reversal process is analogous to that found in barium titanate single crystals. The activation fields are of the same order of magnitude in the two ferroelectrics, although the domain mobility of GASH is 30 to 100 less than that of BaTiO3 at room temperature. Neither a threshold field nor a true coercivity was found for GASH and the hysteresis losses in this material are less by a factor of 10 in comparison with barium titanate. The upper frequency limit for observing ferroelectric phenomena appears to be about 25-50 kc in both materials. It is concluded that while GASH has some advantages over BaTiO3 as a possible electronic component in terms of lower hysteresis losses, ease of crystal growth, and lower electromechanical activity, its use at the present stage of development must be limited to low speed (less than 1 kc) switching circuits.