Spin dynamics in exchange-biased F/AF bilayers

Abstract

The spin dynamics of the ferromagnetic pinned layer of ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad frequency range (30 MHz-6 GHz). A phenomenological model based on the Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is proposed. The experimental results are compared to theoretical predictions.Comment: 12 pages, 3 figures, 1 tabl

Hysteresis from antiferromagnet domain-wall processes in exchange biased systems

“…(4) and indicates that the interfacial antiferromagnet spins are largely collinear with the ferromagnet outside the region of wall formation. Similar features have been observed in experiment [10].…”

The step effect of hysteresis loop in FM/AFM mixed magnetic system

“…Recently the exchange bias properties of FM/AFM mixed magnetic systems [1][2][3][4] are widely discussed because of its significance to understanding some interesting magnetic phenomena. On account of zero magnetization in virgin state, the site-diluted antiferromagnets [5][6][7][8] have attracted many researchers' interests.…”

Hysteretic resonance frequencies and magnetization reversal in exchange biased polycrystalline F/AF bilayers

“…The broadening of the high-frequency response may be due to a distribution of local exchange fields because of the polycrystallinity of the samples. It is well known [28,24] that the theoretical value of m 0 ð0Þ at low frequency behaves like 1 þ ðM s =H eff ) and, as observed, the enhancement of the effective field due to exchange biasing leads to a reduction of the level of m 0 ð0Þ: With respect to the magnetization precession, the exchange bias leads to the enhancement of the resonance frequency.…”

“…It gives exchange field values several times higher than the ones obtained with HL measurements [24]. Thus, interface coupling models that reconcile these measurements are very important since only a few authors have carried out spin dynamic calculations associated with magnetization reversal in the case of strong asymmetry observed in the hysteresis loops measurements.…”

“…The technique of measuring complex permeability frequency spectra (CPS) of exchange biased bilayers [23,24] has drawn less attention. It gives exchange field values several times higher than the ones obtained with HL measurements [24].…”