https://doi.org/10.1140/epjb/e20020060
Memory against temperature or electric field sweeps in potassium niobo-tantalate crystals
Laboratoire des Milieux Désordonnés et Hétérogènes (Associated with the Centre National de la Recherche Scientifique) ,
Université P. et M. Curie, Case 86, 75252 Paris Cedex 05, France
Corresponding author: a dous@ccr.jussieu.fr
Received:
28
May
2001
Revised:
10
October
2001
Published online: 15 March 2002
Aging, memories after temperature sweeps (double ramp and double jump) and
memories after electric field sweeps (double ramp and double jump) were studied as a
function of frequency. The experiments were performed at low temperatures in the
ferroelectric phase of two potassium niobo-tantalate crystals K Ta
NbxO3 with the
niobium concentration x close to 0.02. Five complex quantities are defined, which
respectively characterize these five phenomena. The main feature is that isothermal aging and
memories after temperature sweeps have exactly the same frequency dependence while after
electric field sweeps the frequency dependence is clearly different. Additionally, the role of
the characteristics of the sweeps (amplitudes, rates of changes, durations) on these memories
were measured. The observed behaviours are discussed in term of a model which attributes
the time dependent effects to growth and reconformation of ferroelectric domains and takes
into account that the domain wall motion is hindered by pinning sites. The difference in the
frequency dependences against the nature of the swept parameters shows that the distribution
of the reconformation time is sensitive to the biasing electric field.
PACS: 77.22.Gm – Dielectric loss and relaxation / 78.30.Ly – Disordered solids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
