Microwave Absorption in La1.5Sr0.5NiO4/CoFe2O4 Nanocomposites (Revised Feb. 2014)

作者：Xuan Chu T A^*; Tho Pham T; Quang Doan M; Bach Ta N; Thanh Tran D; Le Ngo T H; Manh Do H; Phuc Nguyen X; Nam Dao N H

来源：IEEE Transactions on Magnetics, 2014, 50(6): 2502804.

DOI：10.1109/TMAG.2014.2306693

• Impedance matching
• microwave absorption
• phase matching
• radar absorption

La1.5Sr0.5NiO4 is well known as a dielectric material that has a colossal permittivity ( up to 10(7)) and a weak paramagnet at room temperature. The permeability is about 1.005, which is just slightly larger than that of air. The weak magnetic moment together with the huge imbalance between permittivity and permeability seemed to negate La1.5Sr0.5NiO4 as a promising candidate for electromagnetic absorption due to the lack of magnetic losses. However, we have found that La1.5Sr0.5NiO4 nanopowder indeed has a reasonably strong microwave absorption capability in the range of 4-18 GHz. Apparently, impedance matching (vertical bar Z vertical bar = Z(0) = 377 Omega) is found to be responsible for the absorption resonance that shifts to lower frequencies with increasing the absorber's thickness. To improve magnetic losses, as well as to balance out the dielectric and magnetic components, CoFe2O4 nanoparticles are gradually added to the La1.5Sr0.5NiO4/CoFe2O4 composites. The influence of adding magnetic nanoparticles on reflection loss, resonance frequency, and matching effects will be discussed.

• 出版日期2014-6