稀土元素对W型钡铁氧体微波吸收特性的作用

采用化学共沉淀法制备W型钡铁氧体,研究稀土元素Dy、Nd、Pr掺杂对铁氧体微波特性的作用.发现:稀土元素的掺入能有效调整铁氧体的微波电磁参数,使自然共振频率向高频移动,并明显提高试样的高频弛豫特征,同时减小复介电常数,以利于阻抗匹配.在一定范围内增大Dy的掺杂量x,有利于进一步获得低介电损耗和高磁损耗,用数值计算模拟方法得到x=0.05时匹配厚度下铁氧体在2～18GHz范围的反射率曲线:吸收峰值达-52.34dB,吸收率小于-10dB的带宽7.9GHz,结果表明稀土Dy掺杂有利于制备轻、薄铁氧体吸波材料.

Effect of rare earth substitution on microwave-absorbing properties of W-type barium ferrite

W-type hexagonal ferrites were prepared by chemical coprecipitation method.The effect of Dy,Nd and Pr substitution on magnetic properties were analyzed.The results show that rare earth elements substitution can adjust hyperfine parameters magically.An obvious increase in natural resonance frequency and high frequency relaxation characteristics and a strong decrease of complex permittivity have been observed.Suitable Dy content is useful to obtain higher magnetic loss and lower electrical loss.Furthermore,the reflection loss of one-layer absorber with Dy-substituted ferrite was calculated.For the specimen of x=0.05,the maximal reflection loss is-52.34dB,and the bandwidth(with respect to-10dB reflection loss) is 7.9 GHz at a matching thickness of 2.6mm. The result indicates that Dy substitution is useful for thin and wideband ferrite absorber.