Monocrystals with the nominal composition, Bi2V0.9Cu0.1O5.35, were grown from the melt and the crystal structure was studied by using X-ray diffraction techniques. The impedance of the crystals (Pt electrodes) was measured at frequencies ranging from 0.00147Hz to 10MHz and temperatures of between 370 and 990K. It was found that the conductivity was more than 100 times larger in directions parallel to the layers of the inter-growth structure, than in the perpendicular direction (tables 27 and 28). A time dependence of the conductivity was observed within a limited temperature range.

P.Kurek, J.R.Dygas, M.W.Breiter: Solid State Phenomena, 1994, 39-40, 247-50

 

 

 

Table 27

Conductivity of Bi2V0.9Cu0.1O5.35

 

Orientation

Thermal Cycle

T (K)

500K (S/cm)

900K (S/cm)

parallel

first cooling

630-370

4.3 x 10-5

-

parallel

second heating

370-650

5.0 x 10-5

-

parallel

second cooling

630-380

2.1 x 10-5

-

parallel

first cooling

960-700

-

0.26

parallel

second heating

840-990

-

0.24

parallel

second cooling

990-710

-

0.25

perpendicular

first cooling

625-470

5.2 x 10-8

-

perpendicular

second heating

480-660

4.5 x 10-8

-

perpendicular

second cooling

625-465

3.9 x 10-8

-

perpendicular

first cooling

960-700

-

0.0022

perpendicular

second heating

840-990

-

0.0021

perpendicular

second cooling

990-710

-

0.0021

 

 

 

Table 28

Activation Energies for Conductivity in Bi2V0.9Cu0.1O5.35

 

Orientation

Thermal Cycle

T (K)

E (eV)

parallel

first cooling

630-370

0.675

parallel

second heating

370-650

0.675

parallel

second cooling

630-380

0.700

parallel

first cooling

960-700

0.51

parallel

second heating

840-990

0.50

parallel

second cooling

990-710

0.50

perpendicular

first cooling

625-470

0.94

perpendicular

second heating

480-660

0.95

perpendicular

second cooling

625-465

0.95

perpendicular

first cooling

960-700

0.78

perpendicular

second heating

840-990

0.84

perpendicular

second cooling

990-710

0.79