Long range B-site cation ordering and Briet–Wigner–Fano line shape of A1g-like Raman mode in Nd1−xSmx(Mg0.5Ti0.5)O3 microwave dielectric ceramics

Nd1−xSmx(Mg0.5Ti0.5)O3 (x = 0.0–1.0) samples were prepared by solid-state reaction method. Rietveld refinement of X-ray diffraction data was done using P21/n space group with monoclinic symmetry, which supports 1:1 B-site cation ordering. Long range ordering (LRO) parameter decreased up to x = 0.5 and then found to increase with further increase in Sm concentration. The A1g-like mode in Raman spectra was observed to possess Briet–Wigner–Fano line shape. The variation in obtained line width of the A1g-like mode supported LRO. Microwave dielectric characteristics such as dielectric constant (ɛr), quality factor (Q) and temperature coefficient of resonant frequency (τf) were measured in the range of 7–9 GHz. ɛr decreased from 26.5 to 24.9 and τf become less negative from −58 ppm/°C to −36 ppm/°C with increase in Sm concentration. Q × f decreased from 47,500 GHz (for x = 0) to 39,800 GHz (for x = 0.5) and then increased to 44,600 GHz (for x = 1).

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► Q × f of Nd1–xSmx(Mg0.5Ti0.5)O3 are correlated with B-site cation ordering (LRO).
► Correlation between LRO and Γ of A1g-like mode in Raman spectrum is observed.
► Reason for asymmetry in A1g-like Raman mode in these materials is revealed.
► Briet–Wigner–Fano resonance is confirmed with temperature variation in Raman spectra.