High unipolar strain in samarium-doped potassium–sodium niobate lead-free ceramics

Abstract

In this work, a high unipolar strain has been developed in the 0.9675KNNST–0.0325(Bi1−xSmx)NKZ ceramics by introducing Sm, and the composition dependence of their phase structures and electrical properties is also discussed.

Reduced degree of phase coexistence in KNN-Based ceramics by competing additives

“…Therefore, the gradually increased TO-T is reasonably anticipated if one reduces the content of Bi3+, which is demonstrated in this work and other studies [48][49][50]. When progressively replacing Bi3+ with isovalent ions (such as Sm3+, La3+, and Ho3+), the monotonic increase in phase transition temperatures (e.g., rhombohedral-tetragonal phase transition temperature TR-T and TO-T) was clearly observed [48][49][50]. Sm3+, La3+, and Ho3+ show the comparable ion radius but the much lower electronegativity to Bi3+ 17 (see Table 3), resulting in the still strong ionic bond character in Sm-O/La-O/Ho-O bonding.…”

Electrocaloric effect and pyroelectric performance in (K,Na)NbO3‐based lead‐free ceramics

“…It is found that the average grain sizes of the ceramics diminish dramatically with the increase of the BNZ content, which exhibits a strongly compositional dependence. 41,42 Figure 6 displays the electric field dependence of the polarization (P-E) loops under 50 kV cm -1 of KNN-xBNZ ceramics measured at different temperatures. We can find that all elements are uniformly distributed in the element mapping of the ceramics as shown in Figure S2, proving the composition of large grains is same as the smaller one.…”

“…These results are well consistent with previous reports. 41,42 Figure 6 displays the electric field dependence of the polarization (P-E) loops under 50 kV cm -1 of KNN-xBNZ ceramics measured at different temperatures. It is discovered that the saturation polarization (P s ) monotonically declines with the rise of temperature, and the P-E loops exhibit a change from "squared" shape to "slanted" shape as BNZ content increases from 0.03 to 0.06, indicating the reduced ferroelectric stability of the ceramics with higher BNZ content.…”

Structural and piezoelectric properties of textured NLKNS‐CZ thick films and their application in planar piezoactuator

“…[17][18][19][20][21] However, NKN-related piezoceramics with T-O, T-R, and T-O-R multi-structures exhibited large d 33 values. 6,[22][23][24][25] Specifically, a large d 33 of 650 ± 20 pC/N was observed from the NKN-related piezoceramic with the T-O-R multistructure. 26 NKN-related piezoceramics have the pseudocubic (PC) structure at the temperature close to T C , and the PC structure has been identified as the R3m rhombohedral structure.…”

“…NKN‐related piezoceramics with the O‐R multi‐structure exhibited a relatively small d 33 value ranging between 200 pC/N and 260 pC/N 17–21 . However, NKN‐related piezoceramics with T‐O, T‐R, and T‐O‐R multi‐structures exhibited large d 33 values 6,22–25 . Specifically, a large d 33 of 650 ± 20 pC/N was observed from the NKN‐related piezoceramic with the T‐O‐R multi‐structure 26 …”