Influence of Bi Substitution on the Microstructure and Dielectric Properties of Gd3Fe5O12 Ceramics

Rajan, Athira; Das, Sikha L.; Sibi, K.S.; Subodh, G.

doi:10.1007/s11664-018-06844-6

Cited by 11 publications

(4 citation statements)

References 31 publications

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“…Further, it is well known that at high temperatures, there will be a mutual existence of Fe 2+ and Fe 3+ ions in ferrite ceramics . As the formation temperature of SFO is above 1100 °C, the presence of Fe 2+ ions is expected due to the reduction of Fe 3+ ions in the compound . Even though many factors such as electron polarization, ion vibration, and ionic migration are responsible for the loss in ferrites, the electron exchange interactions between the ferric and ferrous ions leading to ion migration loss is the most significant factor responsible for the dielectric loss in ferrites .…”

Section: Resultsmentioning

confidence: 99%

“…43 As the formation temperature of SFO is above 1100 °C, the presence of Fe 2+ ions is expected due to the reduction of Fe 3+ ions in the compound. 44 Even though many factors such as electron polarization, ion vibration, and ionic migration are responsible for the loss in ferrites, the electron exchange interactions between the ferric and ferrous ions leading to ion migration loss is the most significant factor responsible for the dielectric loss in ferrites. 43 Moreover, the low dielectric loss of the LMO also plays an important role in decreasing the dielectric loss of the composites.…”

Section: Methodsmentioning

confidence: 99%

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Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Rajan

Solaman

Subodh

2021

ACS Appl. Electron. Mater.

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A sustainable cold-sintering process was adopted to fabricate composites of (1–x)SrFe12O19–xLi2MoO4, x = 0.4, 0.5, 0.6, and 0.7 with density up to 91%, and their broad-band electromagnetic properties were deciphered. X-ray diffraction (XRD) analysis revealed the coexistence of SrFe12O19 (SFO) and Li2MoO4 (LMO) phases in the composites, unaccompanied by any additional phases. The evolution of microstructure facilitating enhanced densification was observed with an increase in the LMO volume fraction. The real permittivity (ε′) increased with an increase in the LMO volume fraction, while the dielectric loss (tan δε) decreased. Further, the real permeability (μ′) of all of the composites is greater than unity and the magnetic loss (tan δμ) is of the order of 10–2. The 0.3SFO–0.7LMO composite with the highest densification possess ε′ = 6.7, tan δε = 2 × 10–3, μ′ = 1.14, and tan δμ = 2 × 10–2 at 900 MHz along with an appreciable room-temperature saturation magnetization (M s) of 32.2 emu/g. To demonstrate the application potential of this magnetodielectric composite toward microwave antenna applications, a ferrite resonator antenna (FRA) integrated using the SFO–LMO composite was designed, simulated, and fabricated. The fabricated FRA resonating at 12.89 GHz exhibited an exceptionally high return loss of −40 dB and a wide impedance bandwidth of 510 MHz. The remarkable properties of the fabricated ferrite resonator antenna suggest that it is a potential candidate for Ku-band applications.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Rajan

Solaman

Subodh

2021

ACS Appl. Electron. Mater.

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“…Gadolinium iron garnet (Gd 3 Fe 5 O 12 , GdIG) is a transparent ferromagnetic insulator with a garnet structure. It is a high-k material with a considerable dielectric constant (approximately 11.9) 13 and superior insulating properties even at a very thin thickness, effectively minimizing the device size. The thickness and uniformity can be precisely controlled by magnetron sputtering technology.…”

Section: Introductionmentioning

confidence: 99%

High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction

Yang

Wang

et al. 2022

Microsyst Nanoeng

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Graphene/silicon Schottky junctions have been proven efficient for photodetection, but the existing high dark current seriously restricts applications such as weak signal detection. In this paper, a thin layer of gadolinium iron garnet (Gd3Fe5O12, GdIG) film is introduced to engineer the interface of a graphene/silicon Schottky photodetector. The novel structure shows a significant decrease in dark current by 54 times at a −2 V bias. It also exhibits high performance in a self-powered mode in terms of an Ilight/Idark ratio up to 8.2 × 106 and a specific detectivity of 1.35 × 1013 Jones at 633 nm, showing appealing potential for weak-light detection. Practical suitability characterizations reveal a broadband absorption covering ultraviolet to near-infrared light and a large linear response with a wide range of light intensities. The device holds an operation speed of 0.15 ms, a stable response for 500 continuous working cycles, and long-term environmental stability after several months. Theoretical analysis shows that the interlayer increases the barrier height and passivates the contact surface so that the dark current is suppressed. This work demonstrates the good capacity of GdIG thin films as interlayer materials and provides a new solution for high-performance photodetectors.

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“…Owning to the high chemical and physical stabilities, garnet-type A 3 B 2 C 3 O 12 materials are well-known materials for lasers, phosphors, and dielectrics [5]. In recent years, different kinds of low ε r ceramics with garnet structure have been developed, such as vanadates Ca 5 A 4 (VO 4 ) 6 (A = Mg and Zn), aluminates Y 3 MgAl [6][7][8][9][10]. However, large negative τ f for vanadates and high densification temperature for aluminates are unfavorable in commercialization, and tellurate and tungstate are unacceptable for their lowquality factor.…”

Section: Introductionmentioning

confidence: 99%

Structure, Raman spectra and microwave dielectric properties of novel garnet-type Ca₃MZrGe₃O₁₂ (M = Co, Zn) ceramics

Su¹,

Fang

et al. 2021

Journal of Asian Ceramic Societies

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Two novel garnet-type ceramics Ca 3 MZrGe 3 O 12 (M = Co and Zn) with pure phase were prepared through a solid-state reaction method. Structure-property relationships were studied by the Rietveld refinement and Raman spectra. The appearance of two weak symmetric stretching vibrational peaks in Ca 3 ZnZrGe 3 O 12 might be due to the lower ordering. Higher Q × f value in Co-analogue was related to the larger packing fraction and the lower FWHM of A 1g mode. The smaller oxygen bond valence in Ca 3 CoZrGe 3 O 12 indicates a smaller τ f value. At the optimized sintering temperature of 1280 °C, Ca 3 CoZrGe 3 O 12 shows desirable microwave dielectric properties with ε r of 10.37, Q × f value of 60,100 GHz, and τ f value of −28.5 ppm/ o C. The Ca 3 ZnZrGe 3 O 12 ceramic sintered at 1200 °C has the best microwave dielectric properties with ε r of 10.48, Q × f value of 49,700 GHz, and τ f value of −35.8 ppm/ o C.

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Influence of Bi Substitution on the Microstructure and Dielectric Properties of Gd3Fe5O12 Ceramics

Cited by 11 publications

References 31 publications

Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction

Structure, Raman spectra and microwave dielectric properties of novel garnet-type Ca₃MZrGe₃O₁₂ (M = Co, Zn) ceramics

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Influence of Bi Substitution on the Microstructure and Dielectric Properties of Gd3Fe5O12 Ceramics

Cited by 11 publications

References 31 publications

Cold Sintering: An Energy-Efficient Process for the Development of SrFe12O19–Li2MoO4 Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Cold Sintering: An Energy-Efficient Process for the Development of SrFe12O19–Li2MoO4 Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction

Structure, Raman spectra and microwave dielectric properties of novel garnet-type Ca3MZrGe3O12 (M = Co, Zn) ceramics

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Product

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Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Cold Sintering: An Energy-Efficient Process for the Development of SrFe₁₂O₁₉–Li₂MoO₄ Composite-Based Wide-Bandwidth Ferrite Resonator Antenna for Ku-Band Applications

Structure, Raman spectra and microwave dielectric properties of novel garnet-type Ca₃MZrGe₃O₁₂ (M = Co, Zn) ceramics