Tailoring magnetic properties of Al-substituted M-type strontium hexaferrites

Lan, Zhongwen; Wu, Chuanjian; Yang, Changlong; Zhao, Yu; Guo, Rongdi; Wang, Wei; Chen, Chuan; Liu, Xin; Jiang, Xiaona; Sun, Kening

doi:10.1007/s00339-018-2224-y

Cited by 10 publications

(2 citation statements)

References 26 publications

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“…The lattice parameters a, c, and volume obtained from the refinement are found to be decreasing (a = b= (5.888-5.874) Å, c = (23.109-23.085) Å, and V = (693.84-690.28) Å 3 ) with increasing Al 3+ contents. It might be due to substitutions of Al 3+ having smaller ionic radii (r Al3+ ) = 0.53 Å) than Fe 3+ (r Fe3+ ) = 0.67 Å) that causes shrinkage of the lattice parameters [31]. The crystal axis ratio (c/a) is also in the range of (3.92-3.93), which confirms the idealness of M-type hexaferrite [32].…”

Section: Structure and Microstructural Studiesmentioning

confidence: 58%

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping

Singh,

Mohapatra,

Pal

et al. 2023

J. Phys.: Condens. Matter

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The demand for effective microwave-absorbing materials has recently surged due to rapid advancements in electromagnetic (EM) devices. Recently, engineering oxygen vacancies has also become one of the effective ways to develop efficient microwave-absorbing materials. So, understanding the EM absorption mechanism of these materials has become crucial for better engineering of such materials. This article investigates the magnetic properties along with the EM absorption mechanism of M-type hexaferrite, with optimal incorporation of rare-earth element La3+ and doping of transition metal Al3+ cation. The presence of La3+ ions at an optimal level promotes the reduction of Fe3+ to Fe2+ cations and creating oxygen vacancies to offset the electrical charge imbalance. This phenomenon impacts both the magnetic and EM characteristics of the materials. The presence of Fe2+ cations enhanced the spin-orbital interaction, resulting in a strong magnetic anisotropy field along the c-axis. The lowest reflection loss of −36.37 dB at 14.19 GHz, is observed with a bandwidth of 3.61 GHz below −10 dB for x = 0.6. These microwave absorption properties can be attributed to the adequate compensation between dielectric and magnetic losses, which arise from phenomena like dielectric relaxation, magnetic resonance, and conduction loss due to electron hopping between Fe3+ and Fe2+ with proper incorporation of the attenuating constant and excellent impedance matching, along with microstructure of the materials. Furthermore, the material’s exceptional absorption properties are also influenced by the rapid movement of oxygen vacancies from its interior to its surface when exposed to high frequencies, thereby impacting its conductivity. Therefore, it is believed that the regulation of oxygen vacancies can serve as a versatile strategy for developing materials with efficient microwave-absorbing capabilities.

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Section: Structure and Microstructural Studiesmentioning

confidence: 58%

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping

Singh,

Mohapatra,

Pal

et al. 2023

J. Phys.: Condens. Matter

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“…Numerous studies have been conducted to improve the intrinsic magnetic properties of SrM hexaferrites through cation substitutions. Co [11], Ti [12], Al [13], and Zn [14] have been substituted for the Fe sites, while La [15], Nd [16], and Sm [16] have been substituted for the Sr sites. Among these substituents, La-Co co-substitution has been found to be very effective in improving H a without significantly decreasing M s .…”

Section: Introductionmentioning

confidence: 99%

Effects of La-Co Co-Substitution on the Structural and Magnetic Properties of SrM Hexaferrites Prepared by Solid-State Reaction

Lee,

Kang,

Yoo

2024

Applied Sciences

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The effects of La-Co co-substitution on the structural and magnetic properties of strontium M-type hexaferrites (SrM) were carefully investigated for the Sr1−xLaxFe12−xCoxO19 (0.0 ≤ x ≤ 0.3) polycrystalline samples prepared by solid-state reaction in air. Without the use of sintering additives, La-Co co-substituted SrM single phases could be obtained from polycrystalline bulk samples by employing proper processing conditions. The lattice parameter a initially increases with increasing x from 0.0 to 0.1 but gradually decreases with increasing x to 0.20, and then remains almost unaltered up to x = 0.3; the lattice parameter c monotonously decreases with increasing x from 0.0 to 0.25, but it turns to an increase when x = 0.3. The reduction in c/a ratios and Vcell values with increasing x up to x = 0.25 are obviously attributable to the decreasing size effect resulting from La3+ substitution at the Sr2+ site, which surpasses the increasing size effect due to Co2+ and Fe2+ occupancy at the Fe3+ site. Meanwhile, with increasing x from 0.0 to 0.3, while the saturation magnetization (MS) continuously decreases from 75.90 to 72.07 emu/g, the magnetic anisotropy field (Ha) increases from 20.1 to 24.7 kOe, leading to an increase in the intrinsic coercivity (Hci) from 2.68 to 3.99 kOe. The gradual increase in Ha with x, probably caused by a gradual decrease in the crystallographic symmetry, is inversely proportional to the variation in the c/a ratios up to x = 0.25 as usual except when x = 0.3, of which deviation needs further study.

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Crystallographically textured Ba0.8La0.2Fe11.8-Cu0.2O19-δ hexaferrites with narrow FMR linewidth

Lan

et al. 2020

Ceramics International

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Tailoring magnetic properties of Al-substituted M-type strontium hexaferrites

Cited by 10 publications

References 26 publications

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping

Effects of La-Co Co-Substitution on the Structural and Magnetic Properties of SrM Hexaferrites Prepared by Solid-State Reaction

Crystallographically textured Ba0.8La0.2Fe11.8-Cu0.2O19-δ hexaferrites with narrow FMR linewidth

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Tailoring magnetic properties of Al-substituted M-type strontium hexaferrites

Cited by 10 publications

References 26 publications

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La3+-modified M-type hexaferrite with Al3+ doping

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La3+-modified M-type hexaferrite with Al3+ doping

Effects of La-Co Co-Substitution on the Structural and Magnetic Properties of SrM Hexaferrites Prepared by Solid-State Reaction

Crystallographically textured Ba0.8La0.2Fe11.8-Cu0.2O19-δ hexaferrites with narrow FMR linewidth

Contact Info

Product

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Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping

Exploring the role of oxygen vacancies on the magnetic and electromagnetic absorption properties of La³⁺-modified M-type hexaferrite with Al³⁺ doping