Determination of polarization states in (K,Na)NbO3 lead-free piezoelectric crystal

Abstract

Polarization switching in lead-free (K 0.40 Na 0.60)NbO 3 (KNN) single crystals was studied by switching spectroscopy piezoresponse force microscopy (SS-PFM). Acquisition of multiple hysteresis loops on a closely spaced square grid enables polarization switching parameters to be mapped in real space. Piezoresponse amplitude and phase hysteresis loops show collective symmetric/asymmetric characteristics, affording information regarding the switching behavior of different domains. As such, the out-of-plane polarization states of the domains, including amplitudes and phases can be determined. Our results could contribute to a further understanding of the relationships between polarization switching and polarization vectors at the nanoscale, and provide a feasible method to correlate the polarization hysteresis loops in a domain under an electric field with the polarization vector states.

Porous, multi-layered piezoelectric composites based on highly oriented PZT/PVDF electrospinning fibers for high-performance piezoelectric nanogenerators

“…Piezoelectric effect refers to the phenomenon in which the material without a center of structural symmetry changes its internal polarization with external pressure, giving rise to the same amount of heterogeneous charges on the surface. At first, perovskite piezoelectric ceramics ((K, www.springer.com/journal/40145 Na,Li)NbO 3 [1,2], BaTiO 3 [3], and Pb(Zr,Ti)O 3 [4,5]) and piezoelectric semiconductors (ZnS [6], ZnO [7], and CdS [8]) attracted lots of attention due to their excellent piezoelectric coefficients, but the brittleness of their own limited the application in flexible electric devices. On the contrary, piezoelectric polymer has good flexibility but much lower piezoelectric coefficient comparing to the piezoceramics/semiconductors.…”

Electric-Field-Insensitive Temperature Stability of Strain in KNN Multilayer Composite Ceramics

“…Also, the V C increases up to over 7 V for constituent IV. In other words, V C gradually aggrandizes with the addition of BNZ, which is distinguished from the macro-ferroelectric hysteresis loop for bulk piezoelectrics because the V C extracted from SS-PFM can only reflect the local domain switching of ferroelectrics, while the E C extracted from P – E loops reflects the average domain switching of ferroelectrics. , The different V C values of each constituent are caused by various values of the positive coercive bias V 0 + and the negative coercive bias V 0 – (Figure S1a,b), which also give rise to the variation in imprint V i [(| V 0 + | – | V 0 – |)/2] with component (Figure S1c). As indicated by the differences in these parameters, different domain switching behaviors can be found for each component, further suggesting the successful construction of the multilayer composite ceramic with composition/structure gradient effect.…”

Ultrafast synthesis and densification of ZrO2 doped KNN ceramics by reactive flash sintering

“…Potassium sodium niobate ((K,Na)NbO 3 , KNN)-based ceramics are regarded as one of the most promising lead-free piezoelectric ceramics owing to their excellent piezoelectric response and high Curie temperature. [23][24][25][26] To achieve the desired properties of the KNN-based ceramics, doping is a mostly used way to tune their phase compositions, microstructures, and electrical performances. [27][28][29] For example, ZrO 2 is recently served as a dopant into KNN ceramics to suppress the grain growth and manipulate the piezoelectric properties.…”

“…Potassium sodium niobate ((K,Na)NbO 3 , KNN)‐based ceramics are regarded as one of the most promising lead‐free piezoelectric ceramics owing to their excellent piezoelectric response and high Curie temperature 23–26 27–29 .…”