3 research outputs found
Insights into Size-Dominant Magnetic Microwave Absorption Properties of CoNi Microflowers via Off-Axis Electron Holography
In this study, CoNi flower-like hierarchical
microstructures with
different sizes were obtained via a one-step solvothermal method by
simply adjusting the concentration of precursors and surfactant. The
obtained CoNi microflowers possess uniform and tunable size, good
monodispersity, and remarkable magnetic microwave absorption properties
as well as electron holography phase images. Characterization results
have demonstrated the dependency of properties of CoNi microflowers
on their morphologies and sizes. The microflowers exhibit different
stray magnetic fields that might be determined by whether the pristine
nanoflakes on the flowers’ surface was parallel or perpendicular
to grid plane. And as the size of microflowers increased, the coercive
force (Hc) value decreased while saturation magnetization (Ms) value
gradually increased, and it can be also observed that the values of
Ms and Hc at 5 K are higher than those at 300 K. In addition, the
blocking temperature decreased when size increased. Typically, the
2.5 μm CoNi microflowers achieve the maximum reflection loss
(RL) value of −28.5 dB at 6.8 GHz with a thickness of 2 mm,
while on the other hand, the 0.6 μm flowers achieved a broader
absorption bandwidth below −10 dB of 6.5 GHz. Therefore, it
is believable that the CoNi flowers with different sizes and hierarchical
structures in this work have great potential for high performance
magnetic microwave absorption applications