The spectra analysis and microwave dielectric properties of [Ca_0.55(Sm_1‐xBi_x)_0.3]MoO₄ ceramics

Abstract

A series of low‐temperature firing ceramics with scheelite structure, [Ca0.55(Sm1‐xBix)0.3]MoO4 (x = 0.2–0.95), were prepared via solid‐state reaction. The sintering temperature ranges from 660 to 760°C. A standard tetragonal scheelite phase was formed without secondary phase. When the x value was 0.95, the temperature coefficient of resonant frequency (τf) moved to a near zero value (−2.1 ppm/°C) with a dielectric constant 13.7 and the quality factor (Qf) of 33 200 GHz. The Raman spectra shows that the more vibration modes appeared with x value, which is due to the increasing of Bi concentration and results in increase in permittivities and decrease in Qf values. The classical harmonic oscillator model is used in the infrared spectra and extrapolate to the microwave range. The [Ca0.55(Sm1‐xBix)0.3]MoO4 ceramics show high‐performance microwave dielectric properties at low‐sintering temperature.

Ultrahigh Energy Density of Antiferroelectric PbZrO3‐Based Films at Low Electric Field

“…e) The comparison of W rec between PZO‐based AFE films in this work and other representative dielectric materials. [ 6,26,30,35–46 ] f) Temperature dependent dielectric constant and dielectric loss for PLZ(5) films. g) Cycle reliability, h) frequency stability, and i) temperature stability of energy storage properties for representative PLZ(5) films.…”

“…[ 25 ] A decreased t value generally corresponds to an enhanced AFE stability, while many other factors have also been considered to be associated with AFE stability in AgNbO 3 ‐based and NaNbO 3 ‐based materials, including polarizability and electronegativity, [ 26–28 ] and therefore further research is desired. The isovalent/aliovalent doping of Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Li + , and Bi 3+ , replacing Pb 2+ at the A‐site of PZO‐based films [ 29–32 ] have been extensively studied, however, the underlying doping mechanism that impacts phase competition stability and polarization switching remains unclear. Taking into account the previous literature [ 29–30 ] and our own experimental findings (Figure S1, Supporting Information), it has been determined that an optimized content of chemical doping in PZO films typically ranges from 4 to 6 mol%.…”

“…The isovalent/aliovalent doping of Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Li + , and Bi 3+ , replacing Pb 2+ at the A‐site of PZO‐based films [ 29–32 ] have been extensively studied, however, the underlying doping mechanism that impacts phase competition stability and polarization switching remains unclear. Taking into account the previous literature [ 29–30 ] and our own experimental findings (Figure S1, Supporting Information), it has been determined that an optimized content of chemical doping in PZO films typically ranges from 4 to 6 mol%. Herein, a fixed 5 mol% addition of La 3+ (aliovalent dopant) and Sr 2+ (isovalent dopant) with similar ionic radius were chosen to replace Pb 2+ at the A‐site, attempting to enhance the polarization switching ability (enlarge Δ P ) and reduce differences in phase competition stability (Δ E ).…”