Effect of pressure on dielectric and ferroelectric properties of bismuth vanadate

Dielectric constant and dielectric loss studies have been made on polycrystalline (with both random and partial grain orientation) and single-crystal samples of Bi2VO5.5. Both the dielectric constant and the dielectric loss decrease with increasing pressure for all the samples, although the decrease is appreciable in the case of partially grain oriented samples. On application of moderate pressures, unpoled single crystals exhibit ferroelectric hysteresis loops very similar to that of the electrically poled single crystals at room pressure. Similar behaviour has been observed in the case of random and partially grain oriented polycrystalline samples. Beyond about 2 GPa, the samples do not exhibit normal ferroelectric hysteresis loops.