Picosecond Magnetization Dynamics of Single-Crystal Fe$_{3}$O$_{4}$ Thin Films

Bunce, C.; Wu, Jing; Long, Yu; Xu, Y. B.; Chantrell, R.W.

doi:10.1109/tmag.2008.2001337

Cited by 10 publications

(8 citation statements)

References 14 publications

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“…[6][7][8] More recently time resolved magneto-optical Kerr effect measurements have been carried out on 6 nm thick Fe 3 O 4 grown on GaAs to investigate the time resolved precession. 9 The resulting Gilbert damping parameter of ␣ Ϸ 0.1 is more than one order of magnitude larger than typically found for 3d ferromagnetic metal thin films. 10 Note, however, that the large lattice mismatch of Fe 3 O 4 and GaAs ͑around Ϫ5%, when the Fe 3 O 4 cell is rotated by 45°with respect to the GaAs cell in the ͑100͒ plane 11 ͒ makes GaAs less suitable for growing high quality epitaxial Fe 3 O 4 thin films.…”

Section: Introductionmentioning

confidence: 87%

“…14 In the low thickness limit a significantly lower effective damping of ␣ eff = 0.037Ϯ 0.001 is found than previously reported for Fe 3 O 4 on GaAs. 9 With increasing film thickness up to 100 nm a strong increase in ␣ eff up to about 0.2 is observed which cannot be explained by simple nonuniform spin wave excitations. Possible origins of this effect are discussed.…”

Section: Introductionmentioning

confidence: 88%

“…It is important to note, that the intrinsic Gilbert damping parameter of our high quality epitaxial magnetite thin films is sig-nificantly lower than has been reported for magnetite on GaAs. 9 We ascribe this significant improvement to the reduced lattice mismatch of MgO with respect to Fe 3 O 4 ͓Ϫ0.34% ͑Ref. 14͔͒.…”

Section: Examplesmentioning

confidence: 95%

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Thickness dependence of the effective damping in epitaxial Fe3O4/MgO thin films

Serrano-Guisan¹,

Wu²,

Boothman³

et al. 2011

Journal of Applied Physics

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The precessional magnetization dynamics of high quality epitaxial magnetite ͑Fe 3 O 4 ͒ thin films growth on MgO are investigated by inductive magnetization dynamic measurements in time and frequency domain. An upper bound for the intrinsic Gilbert damping parameter of ␣ 0 = 0.037Ϯ 0.001 is derived, which is significantly lower than previously reported for epitaxial Fe 3 O 4 on GaAs. With increasing film thickness from 5 up to 100 nm a strong increase in the effective damping up to 0.2 is observed which cannot be explained by simple nonuniform spin wave excitations. Possible origins of this effect are discussed.

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Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 88%

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Thickness dependence of the effective damping in epitaxial Fe3O4/MgO thin films

Serrano-Guisan¹,

Wu²,

Boothman³

et al. 2011

Journal of Applied Physics

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“…Dynamic magnetization switching measurements provide essential information for the application of this material system into spintronic devices, such as understanding the ultimate limit of the switching speed [32], [33]. A field-pumped time-resolved magneto-optical Kerr effect (TRMOKE) setup has been used to investigate time-resolved magnetization dynamics of epitaxial Fe O ultra-thin films [34]. The field pulse used to trigger the dynamics has a 10-90% rise time of 350 ps, a decay time of ns, and a peak field of 1 kOe.…”

Section: Static and Dynamic Switchingmentioning

confidence: 99%

Hybrid Spintronic Structures With Magnetic Oxides and Heusler Alloys

Hassan

Wong

et al. 2008

IEEE Trans. Magn.

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Hybrid spintronic structures, integrating half-metallic magnetic oxides and Heusler alloys with their predicted high spin polarization, are important for the development of second-generation spintronics with high-efficient spin injection. We have synthesized epitaxial magnetic oxide Fe 3 O 4 on GaAs(100) and the unit cell of the Fe 3 O 4 was found to be rotated by 45 to match the gallium arsenide GaAs. The films were found to have a bulk-like moment down to 3-4 nm and a low coercivity indicating a high-quality magnetic interface. The magnetization hysteresis loops of the ultrathin films are controlled by uniaxial magnetic anisotropy. The dynamic response of the sample shows a heavily damped precessional response to the applied field pulses. In the Heusler alloy system of Co 2 MnGa on GaAs, we found that the magnetic moment was reduced for thicknesses down to 10 nm, which may account for the lower than expected spin-injection efficiency from the spin-light-emitting diode structures. Using the element-specific technique of X-ray magnetic circular dichroism (XMCD), the reduced spin moments were found to originate from the Mn rather than the Co atoms, and the improvement of the interface is thus needed to increase the spin injection efficiency in this system. Further studies of the I-Vcharacteristics of Fe 3 O 4 /GaAs(100) and Fe 3 O 4 /MgO/GaAs(100) show that the Fe 3 O 4 -based spintronic structures have a well-defined Schottky or tunneling barrier of moderate barrier height, which is encouraging for high-efficient spin injection.

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“…19 The influence of the defects in Fe 3 O 4 thin films has not been investigated and very few studies on the magnetization dynamics and magnetic damping of Fe 3 O 4 thin films have been reported. 20,21 To explore the effects of the structure on magnetic damping, the defect-controlled epitaxial Fe 3 O 4 (111) nanoscale films on Yttria-stabilized Zirconia (YSZ) substrate were prepared by PLD growth and annealing. Using time-resolved magneto-optical Kerr effect (TR-MOKE), we find that the PSSW mode only exists in the annealed defect-free Fe 3 O 4 film, and numerical simulations support this finding.…”

mentioning

confidence: 99%

Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films

Atkinson

Kuerbanjiang

et al. 2019

Applied Physics Letters

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We have investigated the magnetic damping of precessional spin dynamics in defect-controlled epitaxial grown Fe 3 O 4 (111)/Yttria-stabilized Zirconia (YSZ) nanoscale films by all-optical pump-probe measurements. The intrinsic damping constant of the defect-free Fe 3 O 4 film is found to be strikingly larger than that of the asgrown Fe 3 O 4 film with structural defects. We demonstrate that the population of the first-order perpendicular standing spin wave (PSSW) mode, which is exclusively observed in the defect-free film under sufficiently high external magnetic fields, leads to the enhancement of the magnetic damping of the uniform precession (Kittel) mode. We propose a physical picture in which the PSSW mode acts as an additional channel for the extra energy dissipation of the Kittel mode. The energy transfer from Kittel mode to PSSW mode increases as in-plane magnetization precession becomes more uniform, resulting in the unique intrinsic magnetic damping enhancement in the defect-free Fe 3 O 4 film.The photo-induced precessional spin dynamics in various magnetic materials has attracted significant attention since the observation of the uniform magnetic precession (Kittel mode) and the corresponding first-order perpendicular standing spin wave (PSSW mode) in Ni films by the all-optical pump-probe technique. 1,2 After excitation by a femtosecond laser pulse, besides the uniform Kittel mode, different spin wave modes can be stimulated including first-order PSSW and Damon-Eshbach dipolar surface spin waves (DE modes). 3 At the same time, all-optical pump-probe measurements allow determination of the magnetic Gilbert damping α, 4,5 which is a key parameter for magnetic data recording and the nextgeneration spintronic memory devices such as Magnetoresistive Random Access Memory (MRAM) 6,7 . Therefore, understanding and controlling the magnetic damping is of crucial importance. Among many factors affecting the magnetic damping, structural defects are crucial because they are generally inevitable when preparing films or devices. It was proposed theoretically that defects scatter the Kittel mode into short wavelength spin waves via two magnon scattering, producing an extrinsic contribution to magnetic damping. 8 This extrinsic mechanism was verified by the fact that in thin NiFe films the FMR linewidth increases with decreasing thickness. 9

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Picosecond Magnetization Dynamics of Single-Crystal Fe$_{3}$O$_{4}$ Thin Films

Cited by 10 publications

References 14 publications

Thickness dependence of the effective damping in epitaxial Fe3O4/MgO thin films

Thickness dependence of the effective damping in epitaxial Fe3O4/MgO thin films

Hybrid Spintronic Structures With Magnetic Oxides and Heusler Alloys

Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films

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