Pseudomorphic spinel ferrite films with perpendicular anisotropy and low damping

Budhani, R. C.; Emori, Satoru; Galazka, Zbigniew; Gray, Barbara; Schmitt, Maxwell; Wisser, Jacob J.; Jeon, Hyung-Min; Smith, Hadley; Shah, Piyush; Page, Michael R.; McConney, Michael E.; Suzuki, Yuri; Howe, Brandon M.

doi:10.1063/1.5023118

Cited by 20 publications

(12 citation statements)

References 34 publications

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“…This could be due to the participation of more Fe 3+ ions in the formation of the ferrite phase [6]. Therefore, this study points toward the development of ordered phases in the composites due to Al doping by reducing structural defects [43]. As a result of this, the lattice parameters of both the phases did not show any remarkable changes because of Al doping (Table 1) and it is closely matched with the reported values of this system [1].…”

Section: Resultssupporting

confidence: 85%

“…The increase in Al doping results in the appearance of more spots in the SAED pattern, thereby indicating an enhancement of crystallinity in the NC sample. The increase in the number of SAED pattern with increasing 'x' further supports the Al doping-induced suppression of crystal defects in the samples [43]. Most of the nanoparticles are in the agglomeration form for which irregular morphology with core-shell structure has been observed.…”

Section: Resultssupporting

confidence: 58%

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Effect of size, phase fraction and interface coupling on the magnetic behavior of al-modified α-Fe2O3/NiFe2O4 core–shell structure

et al. 2021

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The effect of Al doping on the NiFe 2 O 4 phase for the enhanced magnetic properties of α-Fe 2 O 3 /NiFe 2 O 4 composite has been reported. The crystalline quality of the samples improves significantly with increasing Al doping concentration. The formation of core-shell structure in the samples along with the reduction in shell thickness with Al doping has been evidenced through morphological characterization. All the samples show the optical band gap value of 1.7 eV that could produce higher efficiency toward the visible light absorption. All the samples show the doubly inverted structure (T N > T c ). The low saturation magnetization and high coercivity in the Al-doped samples in comparison with the un-doped sample are observed because of the paramagnetic spin configuration of Al ions and interface coupling between α-Fe 2 O 3 and NiFe 2 O 4 phases. The different exchange coupling in Al-modified α-Fe 2 O 3 /NiFe 2 O 4 composite systems could be associated with the NiFe 2 O 4 phase. The occurrence of narrow band gap, ferromagnetism, loop shift, freezing temperature and doubly inverted structure in the nanocomposite samples could be beneficial for photo-electrochemical water splitting, photo-catalyst and magnetic memory device applications. KeywordsNanocomposite • NiFe 2 O 4 • Core-shell structure • Exchange bias • Doubly inverted structure * P. Mallick

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Section: Resultssupporting

confidence: 85%

Section: Resultssupporting

confidence: 58%

Effect of size, phase fraction and interface coupling on the magnetic behavior of al-modified α-Fe2O3/NiFe2O4 core–shell structure

et al. 2021

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“…Thus, the key ingredients for strong CME and broad-band E-tunable devices are composites with high l and d and small Ms. An equally important parameter is the FMR linewidth DH that must be much smaller than HME for practical devices. This report is on CME effects in composites with single crystal-like epitaxial thin films of nickel ferrite, NiFe2O4 (NFO), with a large l and a much smaller DH than bulk single crystals [26][27][28]. Recent significant efforts in this regard by subsets of the present authors include (i) observation of DH as low as 5 Oe, strain-induced uniaxial anisotropy field Hu of 10 kOe due to strong magnetoelastic interactions, and l ~ 10 ppm for Pulsed Laser Deposited (PLD) NiZnAl-(NZAFO) ferrite films on MgAl2O4 (MAO) substrates [26,27], and (ii) PLD films of NFO on MAO, MgGa2O4 (MGO) and CoGa2O4 (CGO) substrates with Hu ~ 0.5-11.9 kOe and DH ~ 25 Oe [28].…”

Section: Introductionmentioning

confidence: 99%

“…This report is on CME effects in composites with single crystal-like epitaxial thin films of nickel ferrite, NiFe2O4 (NFO), with a large l and a much smaller DH than bulk single crystals [26][27][28]. Recent significant efforts in this regard by subsets of the present authors include (i) observation of DH as low as 5 Oe, strain-induced uniaxial anisotropy field Hu of 10 kOe due to strong magnetoelastic interactions, and l ~ 10 ppm for Pulsed Laser Deposited (PLD) NiZnAl-(NZAFO) ferrite films on MgAl2O4 (MAO) substrates [26,27], and (ii) PLD films of NFO on MAO, MgGa2O4 (MGO) and CoGa2O4 (CGO) substrates with Hu ~ 0.5-11.9 kOe and DH ~ 25 Oe [28]. The smallest DH and highest Hu were measured for NFO films on MGO and CGO substrates with a film-lattice mismatch of 0.8% and 0.2%, respectively, and was attributed to the elimination of undesired anti-phase boundary defects and the influence of strain in the films.…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric Interactions in Composites of Ferrite Films on Lattice-Matched Substrates and Ferroelectrics

Zhou

Singh

et al. 2019

Phys. Rev. Applied

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The nature of mechanical strain-mediated converse magnetoelectric effect (CME) has been studied in multiferroic composites of single-crystal like thin films of nickel ferrite (NFO) and polycrystalline lead zirconate titanate (PZT). Ferrite films of thickness 0.45 to 1 micron were prepared by Pulsed Laser Deposition on lattice-matched (100) and (110) substrates of magnesium gallate (MGO) and cobalt gallate (CGO) that resulted in elimination of antiphase boundaries and magnetic parameters comparable to bulk single crystals. Ferromagnetic resonance under a static electric field E was utilized for studies of CME effects in composites of PZT and NFO films on the substrates. The in-plane static magnetic field H was applied along the principal crystallographic axes of the ferrite film to study its influence on CME.The E-induced ME anisotropy field HME was estimated from FMR data based on shift in resonance frequency with E in order to determine the ME constant A = HME/E. In composites with NFO films on (110) substrates (i) the ME coupling was stronger for films on CGO possibly due to a better lattice match and weaker substrate clamping than for films on MGO, (ii) A-values were the highest for H // [1,-1,0], and (iii) a negative A-value was inferred for H //[001]. For composites with NFO on (100) substrates the strongest ME coupling was measured for H along [001]. A first model for CME that takes into consideration both compressive and bending deformation in the composites is developed and results of the theory are in agreement with both the sign and magnitude of the measured ME coefficient A.The results of the studies presented here indicate the potential for use of the composites in self-biased E-tunable microwave devices.

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“…This behavior corresponds to the quadrivalent heavy transition metal cations on both frequency and permeability allows the customization of the ferrite for specific applications with low loss requirements. The effect of the dopants can be attributed in part to the ionic radii of the dopants and the corresponding distortion to the crystal lattice and its influence upon the magnetocrystalline anisotropy energy 18 and fields.…”

mentioning

confidence: 99%

Broadband free space impedance in Co2Z hexaferrites by substitution of high valency heavy transition metal ions for miniaturized RF devices

Kulik

Winter

Соколов

et al. 2020

Applied Physics Letters

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Polycrystalline samples of Z-type hexaferrites, having nominal compositions Ba3Co2+xFe24-2xMxO41 where M = Ir 4+ , Hf 4+ , or Mo 4+ and x=0 and 0.05, were processed via ceramic processing protocols in pursuit of low magnetic and dielectric losses as well as equivalent permittivity and permeability. Fine process control was conducted to ensure optimal magnetic properties. Organic dispersants (i.e., isobutylene and maleic anhydride) were employed to achieve maximum densities. Crystallographic structure, characterized by X-ray diffraction, revealed that doping with Ir 4+ , Hf 4+ , or Mo 4+ did not adversely affect the crystal structure and phase purity of the Z-type hexaferrite. The measured microwave and magnetic properties show that the resonant frequency shifts depending on the specific dopant allowing for tunability of the operational frequency and bandwidth. The frequency bandwidth in which permittivity and permeability are very near equal (i.e., ~400 MHz for Mo 4+ (x), where x=0.05 doping) is shown to occur at frequencies between 0.2 and 1.0 GHz depending on dopant type. These results give rise to low loss, i.e., tan δ # /ε & = 0.0006 and tan δ ' /µ & = 0.038 at 650 MHz, with considerable size reduction of an order of magnitude, while maintaining the characteristic impedance of free space (i.e., 377±5W). These results allow for miniaturization and optimized band-pass performance of magnetodielectric materials for communication devices such as antenna and radomes that can be engineered to operate over desired frequency ranges using cost effective and volumetric processing methodologies.

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Pseudomorphic spinel ferrite films with perpendicular anisotropy and low damping

Cited by 20 publications

References 34 publications

Effect of size, phase fraction and interface coupling on the magnetic behavior of al-modified α-Fe2O3/NiFe2O4 core–shell structure

Effect of size, phase fraction and interface coupling on the magnetic behavior of al-modified α-Fe2O3/NiFe2O4 core–shell structure

Magnetoelectric Interactions in Composites of Ferrite Films on Lattice-Matched Substrates and Ferroelectrics

Broadband free space impedance in Co2Z hexaferrites by substitution of high valency heavy transition metal ions for miniaturized RF devices

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