Defect‐driven evolution of piezoelectric and ferroelectric properties in CuSb₂O₆‐doped K_0.5Na_0.5NbO₃ lead‐free ceramics

Abstract

Defect greatly affects the microscopic structure and electrical properties of perovskite piezoelectric ceramics, but the microscopic mechanism of defect-driven macroscopic properties in the materials is not still completely comprehended. In this work, K 0.5 Na 0.5 NbO 3 +x mol CuSb 2 O 6 lead-free piezoelectric ceramics were fabricated by a solid-state reaction method and the defect-driven evolution of piezoelectric and ferroelectric properties was studied. The addition of CuSb 2 O 6 induces the formation of dimeric ðCu 000At low doping concentration of CuSb 2 O 6 (0.5-1.0 mol%), DC1 and DC2 coexist in the ceramics and harden the ceramics, inducing a constricted double P-E loop and high Q m of 895 at x=0.01. However, DC2 becomes more dominant in the ceramics with high concentration of CuSb 2 O 6 (≥1.5 mol%) and thus leads to softening behavior of piezoelectricity and ferroelectricity as compared to the ceramic with x=0.01, giving a single slanted P-E loop and relatively low Q m of 206 at x=0.025. All ceramics exhibit relatively high d 33 of 106-126 pC/ N. Our study shows that the piezoelectricity and ferroelectricity of K 0.5 Na 0.5 NbO 3 ceramics can be tailored by controlling defect structure of the materials. K E Y W O R D Sdefects, ferroelectricity/ferroelectric materials, lead-free ceramics, perovskites, piezoelectric materials/ properties

Hardening Effect in Lead-Free KNN-Based Piezoelectric Ceramics with CuO Doping

“…The fitted peaks are displayed in Figure f,g; ν 5 and ν 1 shift to lower wavenumber, but the overall shift is small. Cu 2+ with higher electronegativity and larger radius leads to the distortion of the O–B–O angle as well as the change of the distance between the B-site ion and the coordinated O 2– , which results in the degradation of the ordered structure of the ceramics. , Therefore, the bonding strength of the BO 6 octahedron is reduced, and the vibration strength of the O–B–O bond becomes weaker . Meanwhile, all vibration modes show an increased full width at half-maximum with the rise of CuO content, suggesting the enhanced relaxation.…”

Sharpening polycrystalline phase boundary for potassium sodium niobate ceramics with MnF2 modification

“…24 The lowered grain size is mainly due to the reduced 𝑉 is deemed to promote grain growth. 24,35 All the elements exhibit uniform distribution without any gathering in all the ceramics (Figure S2). Meanwhile, ε r -T curves corresponding to different phase transitions are exhibited in Figure 2A-C.…”

Defects and Aliovalent Doping Engineering in Electroceramics

“…623 Wang et al used a proposed mechanism to explain the defect-driven evolution of inner bias field in the hysteresis loop. 624 The mechanism related to the inner bias field and pinched hysteresis loop will be discussed in Sections 7 and 8.2. In addition, research on the defect induced piezoelectric enhancement in the KNN is abundant.…”

“…Huan et al utilized the thermally stimulated depolarization current to investigate the state of V O in the Sn 4+ doped KNN system . Wang et al used a proposed mechanism to explain the defect-driven evolution of inner bias field in the hysteresis loop . The mechanism related to the inner bias field and pinched hysteresis loop will be discussed in Sections and .…”