Porous Fe₃O₄/SnO₂ Core/Shell Nanorods: Synthesis and Electromagnetic Properties

Abstract

Porous Fe₃O₄/SnO₂ core/shell nanorods are successfully fabricated, in which the width and the length of the pores are 5−10 and 10−60 nm, respectively. We prepared 80 wt % of porous Fe₃O₄/SnO₂ core/shell nanorod-wax composites in order to measure their electromagnetic parameters. The measured results indicate that effective complementarities between the dielectric loss and the magnetic loss are realized over 2−18 GHz frequency range, suggesting the porous Fe₃O₄/SnO₂ core/shell nanorods have excellent electromagnetic wave absorption properties. The reflection loss was calculated in terms of the transmit-line theory. The absorption range under −20 dB is from 3.2 to 16.88 GHz for an absorber thickness of 2−5 mm. Moreover, the porous core/shell nanorods exhibit dual-frequency absorption characteristics and their maximum reflection loss reaches −27.38 dB at 16.72 GHz as the absorber thickness is 4 mm. The excellent microwave absorption properties of the porous Fe₃O₄/SnO₂ core/shell nanorods are attributed to effective complementarities between the dielectric loss and the magnetic loss and the special core−shell structures.