Microwave Shielding Characteristics of ${\hbox{PMMA/BiFeO}}_{3}$ Composites

BiFe
_1-x
Sm
_x
O
₃
composites with different samarium (Sm) concentration (
x
=5-20%) in BFO
₃
were fabricated by the solid-state method. Their structure and magnetic property due to the samarium substitution in BFO
₃
were analyzed by the X-ray diffractometer and vibration sample magnetometer responses, respectively. The complex permeability (μ = μ'-jμ") and shielding effectiveness (SE) of powder-resin composites consisting of magnetic particles (BiFe
_1-x
Sm
_x
O
₃
) embedded into a dielectric matrix (PMMA) were studied at the microwave frequencies. The samarium concentration dependence of permeability and SE was measured using the free-space method. We found that the magnetic properties of the Sm-substitute BFO
₃
mainly lead to the shielding effect for the PMMA/BiFe
_1-x
Sm
_x
O
₃
composites. In this paper, we demonstrate the gradual change of the shielding effect and permeability of the PMMA/BiFe
_1-x
Sm
_x
O
₃
composites in the microwave range.