Enhanced Microwave Absorption Performance in Sr-Modified La2NiO4±δ Nickelate With High Dielectric Loss

Abstract

This work aims to achieve the excellent microwave absorption in layered dielectric nickelate compounds. The phase, microstructure, electromagnetic properties, and microwave absorption of the Sr-modified La 2−x Sr x NiO 4±δ (x = 0, 0.3, 0.5, 0.75) nickelates were investigated, determining and analyzing the role of Sr doping level. All compounds reveal the single tetragonal phase identified as the I4/mmm space group, and the lattice parameters correlate with the doping content, evidenced by Rietveld refinement. By introducing strontium, the pronouncedly increased electronic conductivity contributes to the high dielectric loss, which gives rise to a superior attenuation ability and absorbing bandwidth. A minimum reflection loss of-21.07 dB was found in La 2−x Sr x NiO 4±δ (x = 0.75) at a thickness of 1.9 mm, covering the effective bandwidth of 2.9 GHz. This enhanced microwave absorbing performance in nickelate shows promise in the radar absorbing field.

A Review of Phase-Change Materials and Their Potential for Reconfigurable Intelligent Surfaces

“…The strong electronic-lattice distortions generated by RP defects also led to an MIT of 340 K. Zhong et al presumed this study could guide the growth and performance control of nickelate perovskite oxide films, while The CSD-NNO/LAO thin film is porous, while the other two are dense [22]. (c) SEM micrographs of the fracture surface of La 2-x Sr x NiO 4 ceramics [23]. (d) Schematic representation of SNO structure with random oxygen vacancies, which act as impurity centers.…”

“…They also detailed potential methods to improve the film's properties, such as pore-generating agents or film patterning to grow more granular films and increase the surface area. In [23], Liu et al demonstrated a modified La2NiO4 (LNO) by doping Sr into LNO using a sol-gel method. The phase, microstructure electromagnetic properties, and microwave absorption were investigated.…”

“…In [ 23 ], Liu et al demonstrated a modified La 2 NiO 4 (LNO) by doping Sr into LNO using a sol-gel method. The phase, microstructure electromagnetic properties, and microwave absorption were investigated.…”

“…This variability in volatility is an important consideration when working with PCMs, and researchers are exploring new ways to leverage this unique property to create more dynamic and tunable materials. Examples of volatile PCMs that have been highly studied at the time of this review are vanadium oxides [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ], titanium oxides [ 10 , 11 , 12 , 13 ], iron oxide (Fe 3 O 4 ) [ 14 , 15 , 16 ], lanthanum cobaltite (LaCoO 3 ) [ 17 , 18 ], niobium dioxide (NbO 2 ) [ 19 , 20 ], and rare-earth nickelates ( R NiO 3 ) [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Chalcogenides (Ge 2 Sb 2 Te 5 /Ge 2 Sb 2 Se 4 Te, Sb 2 Se 3 , Sb 2 S 3 ) [ 28 , 29 , 30 , 31 , 32 , 33 ] are among the most studied non-volatile PCMs in the recent literature.…”

“…(b) Cross-sectional HAADF-STEM and the corresponding EDX mappings of Ni and Nd elements.The CSD-NNO/LAO thin film is porous, while the other two are dense[22]. (c) SEM micrographs of the fracture surface of La2-xSrxNiO4 ceramics[23]. (d) Schematic representation of SNO structure with random oxygen vacancies, which act as impurity centers.…”