2024. 01.25

第41回無機材料に関する最近の研究成果発表会～材料研究に新たな風を～

高周波電磁環境を支えるギガヘルツ帯域電磁ノイズ吸収材料～磁性材料と電磁波の相互作用による新たな機能創出～
安川 雪子
千葉工業大学 工学部 電気電子工学科

Objective

Electromagnetic wave absorbers
for high frequency (GHz) noiseFirst study

Ni0.5Zn0.5Fe2O4
Spinel-structured ferrite

Procedures: from Ni0.5Zn0.5Fe2O4 bulk ceramic to sheet
Starting materials
-Fe2O3 (99.9 %), NiO (99.97%), and ZnO (99.997 %) powders
MixtureMixed for 2hrs using mortar and pestle
First sintering
1000 C for 4hrs in AirRegrinding
Formation of pellets

10 MPa for 4min
Second sintering
1400 C for 4hrs in Air

Ni0.5Zn0.5Fe2O4 bulk ceramicProcedures: from Ni0.5Zn0.5Fe2O4 bulk ceramic to sheet
SlurryNi0.5Zn0.5Fe2O4 ceramic powders, ((CH2CH(OH))500 (polyvinyl alcohol), H2O
Sheet formation
Doctor Blade methodDry
105 C for 1h in Air
Stacking of two sheets
150 C for 6min applying 25 kg/cm2 using hot press
Ni0.5Zn0.5Fe2O4-containing sheet

From Ni0.5Zn0.5Fe2O4 bulk ceramic to Ni0.5Zn0.5Fe2O4-containing sheet

5115334222224002202000440

311

Magnetization (emu/g)

100111500-50-100

020Thickness: 225 m40
2 (deg.)

6080-20 -1001020
Applied magnetic field (kOe)

Normalized magnetization (a.u.)

Intensity (cps)

4000

1//
0-1-100

10

Applied magnetic field (kOe)

Y. Yasukawa et al., Scientific Reports, 11 614 (2021).

10Electromagnetic wave absorption

𝝁′′𝒎𝒂𝒙8Permeability

Permeability

Dynamic magnetic properties: complex permeability

0.75 GHz

64
20Frequency

0.0001 0.001 0.01

0.1

1Frequency (GHz)𝒇𝒓 ~ 𝟎. 𝟕𝟓 GHz
Y. Yasukawa et al., Scientific Reports, 11 614 (2021).

10100Permeability

Influence of 𝑯𝒆𝒙 on dynamic magnetic properties: complex permeability
88866644422𝝁′010𝝁′00𝝁′ ′-202𝝁′𝝁′ ′203040-250 01020𝝁′ ′3040-250 01020304050304050

Frequency (GHz)88666Permeability

8442𝝁′

0102042200𝝁′ ′-20𝝁′𝝁′𝝁′ ′𝝁′ ′3040-250 010203040-250 01020Frequency (GHz)

With increasing 𝑯𝒆𝒙 , 𝒇𝒓 also increased
𝒇𝒓 ~ 𝟐𝟓 GHz @𝑯𝒆𝒙 = 𝟕. 𝟎𝟐 kOe
Y. Yasukawa et al., Scientific Reports, 11 614 (2021).

Second study

BaFe12O19
Magnetoplumbite-structured ferrite

Fundamental magnetic properties of bulk ceramic BaFe12O19

OFeBa

Magnetization (emu/g)

𝑴𝒔

𝑯𝒄

BaFe12O19
Applied magnetic field (kOe)
𝑩 𝑩𝐬 𝟒𝝅𝑴𝐬
𝝁= ≅=𝑯 𝑯𝐜
𝑯𝐜
Y. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

Fundamental magnetic properties of bulk ceramic BaCoTiFe10O19

Fe,Co,TiBa

Magnetization (emu/g)

O𝑴𝒔

𝑯𝒄

BaCoTiFe10O19
Applied magnetic field (kOe)

Y. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

From BaCoTiFe10O19 bulk ceramic to BaCoTiFe10O19-containing sheet
500402 (deg.)

60

2014
228
317

220

1011
1110, 209
300
217
2011

203

25

205
206

200, 108

Magnetization (emu/g)

107
114
112

20

110

008

0.5
101102006

Intensity (105 cps)

105] 10-25

80

-50

-20 -100
10
20
Applied magnetic field (kOe)From BaCoTiFe10O19 ceramic bulk to BaCoTiFe10O19-containing sheet

Y. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

Permeability

Dynamic magnetic properties: complex permeability

Frequency (GHz)𝒇𝒓 ~ 𝟒 GHz

Y. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

Procedures: BaCoTiFe10O19 thin film
Starting material
Mixture of Ba, Co, and Ti-cation containing organic solution
Coating

Si substrate
250 rpm for 20 sec
3000 rpm for 30 sec

10 times
Repetition

First heating
100 C for 10min in Air

Second heating
325 C or 350 C for 15min in Air
Sintering800 C to 900 C for 1hr / 840 C for 2hrs in Air

BaCoTiFe10O19 thin film

300 2172011

110 112114 200,108203205206102101Intensity (a.u.)

220

BaCoTiFe
10O19 thin film***** Si

* 900 C880 C860 C820 C1 m

800 C

2040602θ (deg)

Surface

80Thickness: 480 nm

Cross section
SurfaceY. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

Relative permeability

Dynamic magnetic properties: complex permeability

151515𝜇′𝜇 ′′10𝒅 = 𝟓𝟎𝟎 𝝁𝒎
10𝜇′𝜇 ′′𝒅 = 𝟒𝟎𝟎 𝝁𝒎𝜇′𝜇 ′′10𝒅 = 𝟏𝟓𝟎 𝝁𝒎

151055550000-50.1

110-5100 0.1

110-5100 0.1

110Frequency (GHz)

Unclear dynamic magnetic properties

𝒇𝒓 ~ 𝟓 GHz @ 𝟏𝟎𝟎𝝁𝒎???
Y. Yasukawa and C. Takahashi, Electrochemistry, 88 515 (2020).

-5100 0.1𝜇′𝜇 ′′𝒅 = 𝟏𝟎𝟎 𝝁𝒎

110100Conclusion
Electromagnetic wave irradiation

Present study

𝟒~𝟓 GHz

BaCoTiFe10O19 sheets and thin films（株）ノイズ研究所およびパナソニックコネクト（株）より