Tuning the microwave absorption properties of Sr ²⁺ -doped LaMnO ₃ synthesized by solid-state reaction

Microwave absorbing materials are widely investigated due to their high demand in military stealth requirements. The frequency range for most high performance absorbing materials lies in the high frequency K-Ka wave band from 18 to 40 GHz, and materials that can exhibit good absorbing performance in the low frequency S-Ku wave band (2-18 GHz) remain insufficient. This work investigates the microwave absorption properties of LaMnO 3 in the low frequency range tuned by Sr 2+ doping. The replacement of trivalent La 3+ by the divalent Sr 2+ ion introduces defects in the crystal structure, thus influencing the microwave absorption properties. The results show that with increasing Sr 2+ doping concentration, the reflection loss value and the effective absorption bandwidth of LaMnO 3 both enhances and reaches optimal performance at Sr 2+ doping concentration of 0.4. The La 0.6 Sr 0.4 MnO 3 sample exhibits a minimum reflection loss of -23 dB at a frequency of 6 GHz and an effective absorption bandwidth of 2.52 GHz covering the low-frequency C-wave band (4-8 GHz). This work demonstrates potential application of La 1-x Sr x MnO 3 as a low frequency C-wave band absorbing material.