Titanium- and manganese-doped M-type barium hexaferrites with the chemical formula BaFe<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$_{12-x}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>12</mn> <mo>-</mo> <mi>x</mi> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>(Ti<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>Mn<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>)<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$_x$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mi>x</mi> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>O<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$_{19}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>19</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation> (x = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5) were investigated for their potential use in a quarter-wavelength resonant electromagnetic absorber design. The hexaferrites were synthesized via sol–gel auto-combustion and characterized using X-ray diffraction and vibrating sample magnetometry. The complex permeability (<InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\mu = \mu ' -\text{j}\mu ''$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>μ</mi> <mo>=</mo> <msup> <mi>μ</mi> <mo>′</mo> </msup> <mo>-</mo> <mtext>j</mtext> <msup> <mi>μ</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msup> </mrow> </math></EquationSource> </InlineEquation>) was measured in free space using composite samples of the ferrites in polyurethane resin over the frequency range of 16–67 GHz. From the measured permeability, the electromagnetic wave-absorbing characteristics were simulated to achieve maximum reflection loss from a backed absorber for each x value. As the doping concentration was increased, the peak in the imaginary component of the permeability associated with ferromagnetic resonance loss was found to decrease and a corresponding decrease in the effective anisotropy field was also observed. The simulated performance showed that all the Ti–Mn substituted barium hexaferrites had broadband absorption at the 10 dB level. The highest reflection loss was is seen in BaFe<InlineEquation ID="IEq7"> <EquationSource Format="TEX">$_{10}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>10</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>(Ti<InlineEquation ID="IEq8"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>Mn<InlineEquation ID="IEq9"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>)<InlineEquation ID="IEq10"> <EquationSource Format="TEX">$_{2}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>2</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>O<InlineEquation ID="IEq11"> <EquationSource Format="TEX">$_{19}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>19</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation> with a maximum of −21.4 dB at 28.1 GHz. The hexaferrite with the widest bandwidth was BaFe<InlineEquation ID="IEq12"> <EquationSource Format="TEX">$_{10.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>10.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>(Ti<InlineEquation ID="IEq13"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>Mn<InlineEquation ID="IEq14"> <EquationSource Format="TEX">$_{0.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>0.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>)<InlineEquation ID="IEq15"> <EquationSource Format="TEX">$_{1.5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow> <mn>1.5</mn> </mrow> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation>O<InlineEquation ID="IEq16"> <EquationSource Format="TEX">$_{19}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mn>19</mn> <mrow /> </mmultiscripts> </math></EquationSource> </InlineEquation> with an absolute bandwidth of 8.0 GHz at a simulated thickness of 0.73 mm.

Microwave permeability of titanium–manganese-doped M-type barium ferrites

期刊论文
发表日期：

2026年7月23日

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Neil A. Street,
Andrew Amiet

摘要

Titanium- and manganese-doped M-type barium hexaferrites with the chemical formula BaFe $_{12-x}$ $_{12 - x}$ (Ti $_{0.5}$ $_{0.5}$ Mn $_{0.5}$ $_{0.5}$ ) $_x$ $_{x}$ O $_{19}$ $_{19}$ (x = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5) were investigated for their potential use in a quarter-wavelength resonant electromagnetic absorber design. The hexaferrites were synthesized via sol–gel auto-combustion and characterized using X-ray diffraction and vibrating sample magnetometry. The complex permeability ( $\mu = \mu ' -\text{j}\mu ''$ $μ = μ^{'} - j μ^{''}$ ) was measured in free space using composite samples of the ferrites in polyurethane resin over the frequency range of 16–67 GHz. From the measured permeability, the electromagnetic wave-absorbing characteristics were simulated to achieve maximum reflection loss from a backed absorber for each x value. As the doping concentration was increased, the peak in the imaginary component of the permeability associated with ferromagnetic resonance loss was found to decrease and a corresponding decrease in the effective anisotropy field was also observed. The simulated performance showed that all the Ti–Mn substituted barium hexaferrites had broadband absorption at the 10 dB level. The highest reflection loss was is seen in BaFe $_{10}$ $_{10}$ (Ti $_{0.5}$ $_{0.5}$ Mn $_{0.5}$ $_{0.5}$ ) $_{2}$ $_{2}$ O $_{19}$ $_{19}$ with a maximum of −21.4 dB at 28.1 GHz. The hexaferrite with the widest bandwidth was BaFe $_{10.5}$ $_{10.5}$ (Ti $_{0.5}$ $_{0.5}$ Mn $_{0.5}$ $_{0.5}$ ) $_{1.5}$ $_{1.5}$ O $_{19}$ $_{19}$ with an absolute bandwidth of 8.0 GHz at a simulated thickness of 0.73 mm.