Effective Damping Constant and Current Induced Magnetization Switching of GdFeCo/TbFe Exchange-Coupled Bilayers

Higashide, T.; Dai, Bing; Kato, Takeshi; Oshima, Daiki; Iwata, S.

doi:10.1109/lmag.2016.2595502

Cited by 10 publications

(12 citation statements)

References 26 publications

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“…Therefore, it is very essential to study the magnetic dynamics of ferromagnetic films for deeply understanding the fast switching mechanism and manipulating the control parameters of magnetic damping and magnetization precession. However, most of the magnetic dynamics studies are restricted to the individual magnetic thin films. − Relevant work on the exchange-coupled composite system is very rare and limited to the directly contacted case with a fixed coupling strength. − For instance, Barman et al reported a strong dependence of the precession frequency on the NiFe thickness in FePt/NiFe exchange spring bilayers . The damping constant of GdFeCo/TbFe perpendicular exchange-coupled bilayers was found to increase significantly with the TbFe layer thickness .…”

Section: Introductionmentioning

confidence: 99%

“…However, most of the magnetic dynamics studies are restricted to the individual magnetic thin films. − Relevant work on the exchange-coupled composite system is very rare and limited to the directly contacted case with a fixed coupling strength. − For instance, Barman et al reported a strong dependence of the precession frequency on the NiFe thickness in FePt/NiFe exchange spring bilayers . The damping constant of GdFeCo/TbFe perpendicular exchange-coupled bilayers was found to increase significantly with the TbFe layer thickness . Apparently, for the perpendicular FM/RE-TM structure with a controlled interfacial coupling strength ( J ex ), the information of dynamic magnetic properties is lacking.…”

Section: Introductionmentioning

confidence: 99%

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Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films

Tang

Zhao

Zhu

et al. 2018

ACS Appl. Mater. Interfaces

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Dynamic magnetic properties in perpendicularly exchange-coupled [Co/Ni]/Cu (t = 0-2 nm)/TbCo structures show strong dependences on the interfacial antiferromagnetic strength J, which is controlled by the Cu interlayer thickness. The precession frequency f and effective damping constant α of a [Co/Ni] multilayer differ distinctly for parallel (P) and antiparallel (AP) magnetization orientation states. For samples with a thin t, f of the AP state is apparently higher, whereas α is lower than that in the P state, owing to the unidirectional exchange bias effect (H) from the TbCo layer. The differences in f and α between the two states gradually decrease with increasing t. By using a uniform precession model including an additional H term, the field-dependent frequency curves can be well-fitted, and the fitted H value is in good agreement with the experimental data. Moreover, the saturation damping constant α displays a nearly linear correlation with J. It decreases significantly with J and eventually approaches a constant value of 0.027 at t = 2 nm where J vanishes. These results provide a better understanding and effective control of magnetization dynamics in exchange-coupled composite structures for spintronic applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films

Tang

Zhao

Zhu

et al. 2018

ACS Appl. Mater. Interfaces

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“…Details of the TRMOKE setup are described in Refs. [31][32][33][34][35]. The sample stack used for the TRMOKE was SiN (5 nm)/MnGa (50 nm)/Cr (10 nm)/MgO(001), and after ion irradiation, an additional SiN (35 nm) layer was deposited to enhance the Kerr rotation of the MnGa.…”

Section: Magnetization Dynamics Of Ion-implanted Mngamentioning

confidence: 99%

Ion Irradiation for Planar Patterning of Magnetic Materials

2019

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Kr+ ion dose dependence of the magnetic properties of MnGa films and the fabrication of planar-patterned MnGa films by the local ion irradiation technique were reviewed. The magnetization and perpendicular anisotropy of the MnGa vanished at an ion dose of 1 × 1014 ions/cm2 due to the phase change of the MnGa from ferromagnetic L10 to paramagnetic A1 phase. The average switching field Hsw of the planar-patterned MnGa increased with decreasing the bit size, implying low bit edge damage in the patterned MnGa, whereas a rather large switching field distribution (SFD) of 25% was confirmed for a bit size of ~40 nm. Time resolved magneto-optical Kerr effect measurements revealed that as-prepared MnGa exhibits an effective anisotropy field Hkeff = 20 kOe, its distribution ΔHkeff = 200 Oe, and Gilbert damping α = 0.008. The ion-irradiated MnGa films exhibited larger Hkeff = 22–23 kOe than that of the MnGa before the ion dose. Thus, ion irradiation does not decrease the perpendicular anisotropy, which suggests a small bit edge in the patterned MnGa. ΔHkeff increased from 0.2 kOe to 3 kOe, whereas the length of disorder in the film ξ decreased from 10 nm to 3 nm by ion irradiation.

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“…A number of such materials were reported including Ta, 8 Pt, 7 W 21 and other heavy metals as well as topological insulators, 22 metal oxide layers, 23 and so on. The present study discusses thermally assisted STT switching 24,25 and voltage-assisted SOT switching; 26 ] in so doing, results of research done by the authors [27][28][29][30][31][32] are also presented. In addition, the paper introduces results obtained for rare-earth (RE) transition-metal (TM) alloys in terms of SOT switching.…”

Section: Introductionmentioning

confidence: 99%

Progress on Efficient Current Induced Magnetization Switching

2020

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As efficient current-induced magnetization switching schemes, thermally assisted spin transfer torque (STT) switching, spin orbit torque (SOT) switching of rareearth transition metal films, and electric-field-assisted SOT switching were briefly reviewed. For thermally assisted STT switching, hybrid memory layer with a low curie temperature (TC) and high TC layers were found to be effective to reduce the critical current density Jc without sacrificing the thermal stability Δ at room temperature. In SOT switching of GdFeCo, the large SOT was confirmed even at the compensation composition of GdFeCo. In SOT switching of MgO / Co / Pt films, the switching current density Jc was confirmed to be modified around 20% by applying an electric field of 1 V/nm through the insulator film. K E Y W O R D Scurrent-induced magnetization switching, rare-earth transition metal, thermal assist, voltage assist Electr Eng Jpn. 2020;212:3-10.

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Effective Damping Constant and Current Induced Magnetization Switching of GdFeCo/TbFe Exchange-Coupled Bilayers

Cited by 10 publications

References 26 publications

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films

Ion Irradiation for Planar Patterning of Magnetic Materials

Progress on Efficient Current Induced Magnetization Switching

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Effective Damping Constant and Current Induced Magnetization Switching of GdFeCo/TbFe Exchange-Coupled Bilayers

Cited by 10 publications

References 26 publications

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]5/Cu/TbCo Composite Thin Films

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]5/Cu/TbCo Composite Thin Films

Ion Irradiation for Planar Patterning of Magnetic Materials

Progress on Efficient Current Induced Magnetization Switching

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Product

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Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films

Controllable Interfacial Coupling Effects on the Magnetic Dynamic Properties of Perpendicular [Co/Ni]₅/Cu/TbCo Composite Thin Films