Phonon evolution behavior under multi‐field conditions in re‐entrant relaxor NaNbO ₃ decorated with Sb

Abstract Different from the temperature region arrangement of multiple electric orders in traditional relaxor ferroelectrics, re‐entrant relaxor ferroelectrics have attracted extensive attention due to the lower temperature region of disordered relaxation state than that of the long‐range ferroelectric/antiferroelectric order. So, the insight into re‐entrant relaxor ferroelectrics is of great significance for further understanding the abundant relaxor series and revealing the physical origin of relaxation behavior. This present study focuses on the NaNb 0.96 Sb 0.04 O 3 (NNS) ceramic with a room‐temperature antiferroelectric phenomenon, accompanied by a detailed investigation into its re‐entrant relaxation and the underlying mechanism. Dielectric and ferroelectric properties indicate that NNS exhibits a transition sequence of antiferroelectric state→antiferroelectric/relaxation coexistence→relaxation→ferroelectric state during the cooling process from 300 to 80 K. TEM analysis with varying temperature rules out the possibility of structural transition resulting in the re‐entrant relaxation. Further, in‐situ Raman spectra under varying electric fields and temperatures confirm the synergistic influence from the interaction of Na1/Na2 phonon modes and the abnormal mutation of phonon vibration involving the stretching/bending in BO 6 octahedra. This work provides an additional theoretical foundation for multiple transitions of electrical orders in NaNbO 3 ‐based materials. The corresponding analysis can facilitate related design for actual application in technologies.