EFFECT OF PRESSURE ON DIELECTRIC AND FERROELECTRIC PROPERTIES OF BISMUTH VANADATE

Dielectric constant and dielectric loss studies have been made on poly crystalline (with both random and partial grain orientation) and singl e-crystal samples of Bi2VO5.5. Both the dielectric constant and the di electric loss decrease with increasing pressure for all the samples, a lthough the decrease is appreciable in the case of partially grain ori ented samples. On application of moderate pressures, unpoled single cr ystals exhibit ferroelectric hysteresis loops very similar to that of the electrically poled single crystals at room pressure. Similar behav iour has been observed in the case of random and partially grain orien ted polycrystalline samples. Beyond about 2 GPa, the samples do not ex hibit normal ferroelectric hysteresis loops.