Effect of Hydrostatic Pressure on the Hysteresis Loop of Guanidine Aluminum Sulfate Hexahydrate

The 60-cycle hysteresis loop of guanidine aluminum sulfate hexahydrate (G.A.S.H.) has been measured as a function of hydrostatic pressure. It was found that the spontaneous polarization $P_s$ and the coercive field strength $E_c$ increase with pressure. It could be shown that to a first approximation $P_s$ and $E_c$ are a function of the volume change alone, regardless of whether this volume change is obtained by hydrostatic pressure or by lowering the temperature. The measurements suggest that the shortening of the polar $c$ axis causes an increase of the dipole moment along this axis.