High dielectric and microwave absorption properties of ultra-thin 1-xSrTiO_3-δ − xSrAl₁₂O₁₉ films

To reduce the thickness of the microwave absorbing materials, we have prepared 1-xSrTiO_3-δ−xSrAl₁₂O₁₉ ceramics by hot−pressing sintering in the vacuum. The microstructure, dielectric, thermogravimetric analysis and microwave absorbing properties of 1-xSrTiO_3-δ−xSrAl₁₂O₁₉ were systematically investigated and discussed. The 0.95SrTiO_3-δ− 0.05SrAl₁₂O₁₉ has high permittivity, the real part is from 1662.2 to 704.9 and the imaginary part is from 208.6 to 12. The absorption bandwidth (reflection loss ≤−5 dB) of 0.95SrTiO_3-δ− 0.05SrAl₁₂O₁₉ can cover 8.6 − 12.4 GHz and its thickness is only 0.232 mm which is much thinner than these recently reported by other researchers. For 0.942SrTiO_3-δ− 0.058SrAl₁₂O₁₉, the peak value of reflection loss is up to − 58.5 dB with a thickness of 0.75 mm. The 1-xSrTiO_3-δ−xSrAl₁₂O₁₉ films could be excellent candidates for highly efficient and ultra−thin microwave absorbing materials.