Template-assisted synthesis and novel microwave absorption properties of superparamagnetic 2D-nanolamellar Fe3O4

• 2D nanolamellar Fe3O4 (magnetite) (NLM) was synthesized by template method.
• NLM exhibited a superparamagnetic characteristic.
• 8 reflection loss peaks could be found from composite with 50 wt.% NLM.
• The lowest reflectivity was −46.6 dB obtained from composite with 75 wt.% NLM.

Nanolamellar Fe3O4 (magnetite) (NLM) was synthesized by template method. The repeat periodicity of the 2-dimensional nanolamellar structure was 3.72 nm. NLM exhibited a superparamagnetic characteristic with the saturated magnetization 34.8 emu/g. The results showed NLM possessed properties of novel microwave absorption in the frequency range 1–18 GHz. An obvious multiple-reflection loss phenomenon was observed with the increase of matching thickness. For example, 8 reflection loss peaks could be found on the reflection loss curve of NLM/paraffin composite with 50 wt.% NLM at the thickness of 28.0 mm. Compared with NLM/paraffin composite with 75 wt.% NLM, the microwave absorption property of the composite with 50 wt.% NLM was confirmed to be inferior in the 1–10 mm thickness range but superior in the 10–30 mm thickness range. The lowest reflectivity was −46.6 dB obtained from NLM/paraffin composite with 75 wt.% NLM at 7.0 mm thickness. The NLM is a promising microwave absorber.

The dimension of stacked nanosheets is several micrometers. The ordered nanolamellar structure of Fe3O4 can be clearly identified from the parallel sheetlike (Fig. b) and steplike (Fig. c) structure.Figure optionsDownload as PowerPoint slide