Modulation of interfacial magnetic relaxation timeframes by partially uncoupled exchange bias

Abstract A set of partially uncoupled NiFe/Cu/IrMn exchange biased thin films with variable thickness of non-magnetic Cu spacer is characterized by ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) techniques applied complementary to reveal time-scale dependent effects of uncoupling between ferromagnetic and antiferromagnetic layers on high-frequency magnetization dynamics. The results correlate with interfacial grain texture variations and static magnetization behavior. Two types of crystalline phases with correlated microwave response are revealed at the ferro-antiferromagnet interface in NiFe/Cu/IrMn thin films. The first phase forms as well-textured NiFe/IrMn grains with NiFe (111)/IrMn (111) interface. The second phase consists of amorphous NiFe/IrMn grains. Intercalation of NiFe/IrMn by Cu clusters results in relaxation of tensile strains at the NiFe/IrMn interface leading to larger size of grains in both the NiFe and IrMn layers. The contributions of well-textured and amorphous grains to the high-frequency magnetization reversal behavior are distinguished by FMR and BLS techniques. Generation of a spin-wave mode is revealed in the well-textured phase, whereas microwave response of the amorphous phase is found to originate from magnetization rotation dominated by a rotatable magnetic anisotropy term. Under fixed FMR frequency, the increase of Cu thickness results in higher magnetization rotation frequencies in the amorphous grains.

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Complex high-frequency magnetization dynamics and magnetoimpedance in thin films

Physica B Condensed Matter ◽

10.1016/j.physb.2006.05.218 ◽

2006 ◽

Vol 384 (1-2) ◽

pp. 172-174 ◽

Cited By ~ 2

Author(s):

R.B. da Silva ◽

A.D.C. Viegas ◽

M.A. Correa ◽

A.M.H. de Andrade ◽

R.L. Sommer

Keyword(s):

Thin Films ◽

High Frequency ◽

Magnetization Dynamics

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High frequency magnetic properties of ferromagnetic thin films and magnetization dynamics of coherent precession

Chinese Physics B ◽

10.1088/1674-1056/24/5/057504 ◽

2015 ◽

Vol 24 (5) ◽

pp. 057504 ◽

Cited By ~ 4

Author(s):

Chang-Jun Jiang ◽

Xiao-Long Fan ◽

De-Sheng Xue

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

High Frequency ◽

Magnetization Dynamics ◽

Ferromagnetic Thin Films

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Interplay of Linear and Nonlinear Localization Mechanisms in Spin-Torque Oscillators with a Field Well

Ukrainian Journal of Physics ◽

10.15407/ujpe64.10.947 ◽

2019 ◽

Vol 64 (10) ◽

pp. 947 ◽

Cited By ~ 1

Author(s):

R. V. Verba

Keyword(s):

Wave Mode ◽

Spin Torque ◽

Nonlinear Frequency ◽

Magnetization Dynamics ◽

Nonlinear Localization ◽

Generation Mode ◽

Spin Wave Mode ◽

Linear And Nonlinear ◽

Generation Power ◽

Nonlinear Frequency Shift

The magnetization dynamics in a spin-torque oscillator with nonuniform profile of a static magnetic field creating a field well is studied by analytic calculations and numerical simulations. It is demonstrated that, in the case of sufficiently deep and narrow field well, the linear localization in the field well dominates the nonlinear self-localization, despite a negative nonlinear frequency shift. A change of the localization mechanism results in a qualitatively different dependence of the generation power on the driving current. For the dominant linear localization, the soft generation mode is realized, while, for the nonlinear self-localization, we observe a hard mode of auto-oscillator excitation. Simultaneously, a difference in the profiles of the excited spin-wave mode can become evident and distinguishable in experiments only in the case of a nonsymmetric field well.

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Magnetic properties of FeXNi100-X (X=20, 17, 15 %) thin films: focus on high-frequency sensory applications

Materials Science ◽

10.31044/1684-579x-2019-0-8-20-25 ◽

2019 ◽

pp. 20-25

Author(s):

Anna Chlenova ◽

◽

Elizaveta Golubeva ◽

Iuliia Novoselova ◽

Ruslan Salikhov ◽

...

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

High Frequency

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Measurement of Electrical Properties of Superconducting YBCO Thin Films in the VHF Range

Materials ◽

10.3390/ma14123360 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3360

Author(s):

Yakir Dahan ◽

Eldad Holdengreber ◽

Elichai Glassner ◽

Oz Sorkin ◽

Shmuel E. Schacham ◽

...

Keyword(s):

Thin Films ◽

Theoretical Model ◽

Quality Factor ◽

High Frequency ◽

Unit Length ◽

Superconducting Thin Films ◽

Electrical Parameters ◽

Very High Frequency ◽

Production Constraints ◽

Very High

A new measurement technique of electrical parameters of superconducting thin films at the Very High Frequency (VHF) range is described, based on resonators with microstrip (MS) structures. The design of an optimal resonator was achieved, based on a thorough theoretical analysis, which is required for derivation of the exact configuration of the MS. A theoretical model is presented, from which an expression for the attenuation of a MS line can be derived. Accordingly, simulations were performed, and an optimal resonator for the VHF range was designed and implemented. Production constraints of YBa2Cu3O7 (YBCO) limited the diameter of the sapphire substrate to 3″. Therefore, a meander configuration was formed to fit the long λ/4 MS line on the wafer. By measuring the complex input reflection coefficients of a λ/4 resonator, we extracted the quality factor, which is mainly affected by the dielectric and conductor attenuations. The experimental results are well fitted by the theoretical model. The dielectric attenuation was calculated using the quasi-static analysis of the MS line. An identical copper resonator was produced and measured to compare the properties of the YBCO resonator in reference to the copper one. A quality factor of ~6·105 was calculated for the YBCO resonator, three orders of magnitude larger than that of the copper resonator. The attenuation per unit length of the YBCO layer was smaller by more than five orders of magnitude than that of the copper.

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