Investigation on structural and microwave absorption property of Co2+ and Y3+ substituted M-type Ba-Sr hexagonal ferrites prepared by a ceramic method

doi:10.1016/j.jallcom.2016.09.251

Journal of Alloys and Compounds

Volume 695, 25 February 2017, Pages 792-798

https://doi.org/10.1016/j.jallcom.2016.09.251 Get rights and content

Highlights

•
The microwave absorption of Co-Y doped Ba-Sr hexaferrite is reported.
•
x = 0.0 exhibits 96.2% absorbed power at 11.22 GHz and 3.0 mm.
•
x = 1.0 owes 94.7% absorbed power at 10.04 GHz and 2.9 mm.
•
Absorption bandwidth of 336, 500 and 504 MHz is observed.
•
The variation of experimental parameters agree with theoretical models.

Abstract

The Co²⁺ and Y³⁺ ions substituted M-type Ba_0.5Sr_0.5Co_xY_xFe_12-2xO₁₉ hexagonal ferrites (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were synthesized by a standard ceramic method. The phase evolution of prepared hexagonal ferrite samples was studied using X-ray diffraction technique. XRD analysis shows that compositions owe M-type as major phase and BaFe₂O₄ as minor phase. The absorber testing device method is adopted in order to investigate microwave absorption property of prepared ferrite compositions as a function of frequency (8.2–12.4 GHz), substitution and thickness. The microwave absorption property has been evaluated using the quarter wavelength mechanism and impedance matching mechanism. The variation in parameters measured experimentally is in agreement with put forth theoretical models. In doped compositions, the microwave absorption is found to increase with the substitution of Co²⁺ and Y³⁺ ions. Compositions x = 0.0 and 1.0 ascribe good microwave absorber characteristics with absorbed power of 96.2 and 94.7% at 11.22 and 10.04 GHz respectively. The quarter wavelength mechanism contributes for large microwave absorption in compositions x = 0.0, 0.2 and 0.8, whereas impedance matching mechanism is primarily responsible for absorption in x = 0.4, 0.6 and 1.0.

Introduction

The exponential growth in information technology or wireless devices has produced wireless or electromagnetic pollution. The electromagnetic interference (EMI), caused by electromagnetic pollution, results in the malfunctioning of electronic devices and it is potentially harmful for biological systems. The microwave absorbers or EMI suppressors are used to remove or attenuate this EMI or stray electromagnetic signals.

Ferrites are incorporated in electrical, electronic and wireless applications such as wideband transformers, antenna, channel filters, gyromagnetic devices, radar absorbing materials (RAM) etc. [1], [2], [3], [4]. Their good dielectric and magnetic properties render them better EMI suppressers than conventional dielectric materials. M-type hexaferrites are ferrimagnetic by nature and used as microwave absorbers or EMI reduction owing to large dielectric and magnetic losses, domain wall resonance and ferromagnetic resonance (FMR) [5], [6]. The various researchers have investigated microwave absorption properties of M-type substituted hexagonal ferrites [7], [8], [9], [10].

In the present paper, we report microwave absorption property of Co²⁺ and Y³⁺ ions substituted M-type Ba_0.5Sr_0.5Co_xY_xFe_12−2xO₁₉ (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) hexagonal ferrites prepared by a standard ceramic method and elucidated the absorption with quarter wavelength mechanism and impedance matching mechanism; a few researchers have reported the research work based on these two mechanisms.

Section snippets

Experimental method

M-type hexagonal ferrites with chemical composition Ba_0.5Sr_0.5Co_xY_xFe_12−2xO₁₉ (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were prepared by a standard ceramic method [11]. AR grade of Barium carbonate (BaCO₃, 99.98% pure, Merck, Germany), Strontium carbonate (SrCO₃, 99.99% pure, Sigma-Aldrich), Cobalt carbonate (CoCO₃, 99.99% pure, Sigma-Aldrich), Yttrium oxide (Y₂O₃, 99.99% pure, Sigma-Aldrich) and Ferric oxide (Fe₂O₃, 99.99% pure, Merck, Germany) were chosen as starting materials. The stoichiometric

XRD analysis

The structural properties and phase purity of the sintered polycrystalline samples were investigated at room temperature using X-ray diffraction technique. Fig. 2 represents X-ray diffraction patterns of Ba_0.5Sr_0.5Co_xY_xFe_(12−2x) (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) hexagonal ferrite samples, prepared using a standard ceramic method sintered at 1150 °C for 15 h. All the observed peaks in XRD were indexed using the Powder X software and identified with their Millar indices. The observed peaks

Conclusions

The experimental observations are summarised as follows:

1
Ba_0.5Sr_0.5Co_xY_xFe_12-2xO₁₉ (x = 0.0 to 1.0) hexagonal ferrite powders have been successfully synthesized using a standard ceramic method. XRD analysis of undoped and x = 0.2 compositions confirms formation of M-type phase having hexagonal crystal structure, while x = 0.4 to 1.0 composites are consist of two phases; M-type as major phase, hexagonal and BaFe₂O₄ as minor phase, spinel.
2
In doped compositions, the microwave absorption property is

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Journal of Alloys and Compounds

Highlights

Abstract

Introduction

Section snippets

Experimental method

XRD analysis

Conclusions

References (20)

Microwave-absorbing characteristics of epoxy resin composites containing nanoparticles of NiZn and NiCuZn ferrites

Phys. B

Ni–Zn nanoferrite for radar-absorbing material

J. Magn. Magn. Mater.

Tunable complex permeability and enhanced microwave absorption properties of BaNixCo1−xTiFe10O19

J. Alloys Compd.

Tunable microwave absorbing properties of barium hexa-ferrite nano powders by surface carbonized layers

Mat. Lett.

Tunable complex permeability and enhanced microwave absorption properties of BaNixCo1−xTiFe10O19

J. Alloys Compd.

Microstructural and magnetic studies on BaMg_xZn_xX_2xFe_12-4xO₁₉ (X=Zr, Ce, Sn) prepared via mechanical activation method to act as a microwave absorber in X-band

J. Magn. Magn. Mater.

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Microwave absorption of Sr(MnTi)_xFe_12−2xO₁₉ particles

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Near-infrared photo-responsive Er<sup>3+</sup>-K<sup>+</sup> co-doped Y<inf>2</inf>O<inf>3</inf> phosphors with enhanced UC luminescence

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Theoretical and experimental investigations: Synergetic effect of Yb–Cu substitution on different properties of hexagonal ferrites

Role of phase, grain morphology and impedance properties in tailoring of Barium Strontium hexaferrites for microwave absorber/attenuator applications

Effects of Y–Co co-substitution on the structural and magnetic properties of M-type strontium hexaferrites