Advanced
ferroelectrics with a combination of large dielectric
response and good temperature stability are crucial for many technologically
important electronic devices and electrical storage/power equipment.
However, the two key factors usually do not go hand in hand, and achieving
high permittivity is normally at the expense of sacrificing temperature
stability. This trade-off relation is eased but not fundamentally
remedied using relaxor-type materials which are known to have a diffuse
permittivity peak at their relaxor transition temperatures. Here,
we report an anomalous trirelaxor phenomenon in a barium titanate
system and show that it can lead to a giant dielectric permittivity
(εr ≈ 18 000) over a wide temperature
range (T
span ≈ 34K), which successfully
overcomes a long-standing permittivity–stability trade-off.
Moreover, the enhancement in the dielectric properties also yields
a desired temperature-insensitive electrocaloric performance for the
trirelaxor ferroelectrics. Microstructure characterization and phase-field
simulations reveal a mixture of tetragonal, orthorhombic, and rhombohedral
polar nanoregions over a broad temperature window in trirelaxor ferroelectrics,
which is responsible for this combination of giant dielectric permittivity
and good temperature stability. This finding provides an effective
approach in designing advanced ferroelectrics with high performance
and thermal stability.
The mobility of domain walls under an external stimulus plays a crucial role in the piezoelectricity of ferroelectric materials, which usually manifests itself as an irreversible and hysteretic characteristic. Herein, we report a reversible domain-wall motion that contributes almost 55% to the significant piezoelectric response ( d 33 * = 730 pm/V) with low strain hysteresis (H S = 10.76%) at a composition close to the morphotropic phase boundary (MPB) in a (1 − x)Ba(Ti 0.88 Sn 0.12 )O 3 −x(Ba 0.7 Ca 0.3 )TiO 3 system. Such a reversible domain-wall motion is evidenced by the piezo response force microscopy measurement. Moreover, transmission electron microscopy observation indicates a hierarchical domain structure for MPB composition (x = 0.28), and the associated highresolution image suggests the presence of spatial local chemical heterogeneity. Combined with phase field modeling, we reveal that the reversible domain-wall motion is attributed to the asymmetric landau free energy profile as a result of morphotropic phase boundary incorporation with the local heterogeneity. Our work may advance the development of lowhysteretic piezoelectric materials in the application of energy converter or other devices with low energy consumption and high precision.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.