High-coercivity hexaferrite ceramics featuring sub-terahertz ferromagnetic resonance

Abstract

Herein we demonstrate for the first time compact ferrite ceramics with giant coercivity. The materials are manufactured via sintering single-domain Sr0.67Ca0.33Fe8Al4O19 particles synthesized by a citrate-nitrate auto-combustion method. The obtained...

Hard ferrite magnetic insulators revealing giant coercivity and sub-terahertz natural ferromagnetic resonance at 5–300 K

“…297 GHz is the highest reported NFMR frequency among all materials. 24,26 The magnetic contribution (Dm) tends to increase while temperature decreases. The damping factor decreases from 300 K down to 150 K, and the following grows down to 5 K for x = 4-5 samples, while for x = 5.5, it is almost constant with temperature and increases from 40 to 100 GHz only at 5 K.…”

“…In addition, the sintering can even lead to its improvement, for example, due to the effect of the blue shift of the NFMR frequency. 26 High natural ferromagnetic resonance frequencies, tremendous coercivity values, and the possibility of large-scale fabrication of the hexaferrite materials makes them promising for extensive utilization in industry. For example, the hexaferrites can be a base for highly demanded sub-THz detectors and other spintronic devices operating via the spin pumping mechanism, even without an applied magnetic field.…”

Absorption-Dominant mmWave EMI Shielding Films with Ultralow Reflection using Ferromagnetic Resonance Frequency Tunable M-Type Ferrites

“…Since it is known that the FMR frequency of M-type ferrite is proportional to the magnitude of magnetic anisotropy, the concept of changing its magnetic anisotropy to control the FMR frequency band has received 1 3 much attention from many researchers [48]. In particular, the substitution of Fe 3+ ions constituting M-type ferrite into various transition metal ions is considered an effective method to change the magnetic properties of M-type ferrite [49][50][51][52][53][54][55][56][57][58][59][60]. For example, Co 2+ Ti 4+ and Al 3+ are known to be effective elements to decrease and increase magnetic anisotropy, respectively [59,61].…”

In situ annealing achieves an ultrafast synthesis of high coercive strontium ferrite foams and beyond

“…[1][2][3][4][5][6][7][8][9][10][11] The commonly known permanent magnetic materials are SmCo 5 , Nd 2 Fe 14 B, L1 0 -FePt, and ferrites. [12][13][14][15][16][17] However, the complex preparation process, poor corrosion resistance, and high cost of permanent magnetic alloys restrict their large-scale applications. Among the magnetic ferrites, strontium ferrite with high magnetocrystalline anisotropy, cost-effective performance, and chemical corrosion resistance has become a potential candidate for permanent magnetic materials.…”