Magnetism of FePt Surface Alloys

Honolka, Jan; Lee, T. Y.; Kuhnke, Klaus; Enders, Axel; Skomski, Ralph; Bornemann, S.; Mankovsky, S.; Minář, J.; Staunton, J. B.; Ebert, H.; Heßler, M.; Fauth, K.; Schütz, Gisela; Buchsbaum, Andreas; Schmid, Michael; Варга, П.; Kern, Klaus

doi:10.1103/physrevlett.102.067207

Cited by 49 publications

(51 citation statements)

References 18 publications

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“…Moreover, it will also introduce more surface contribution to the magnetic properties, such as the K u , g factor and damping. For instance, the islands exhibit pronounced out-ofplane anisotropy K u , which is peaked when c=0.5 in Fe c Pt (1-c) alloys [50]. This is due to Dzyaloshinski-Moriya interactions emerging at the surface as a result of the broken inversion symmetry, which compete with exchange interactions causing the complex magnetism at the FePt surface.…”

Section: Methodsmentioning

confidence: 99%

“…2(b), the dark contrast in the image corresponds to areas without FePt grown on the MgO substrate. The formation of islands and particles in L1 0 ordered FePt thin films leads to lower chemical order as the Fe-rich clusters are promoted at the surface regions [50]. Moreover, it will also introduce more surface contribution to the magnetic properties, such as the K u , g factor and damping.…”

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confidence: 99%

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Role of antisite disorder on intrinsic Gilbert damping inL10FePt films

et al. 2015

Phys. Rev. B

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The impact of anti-site disorder x on the intrinsic Gilbert damping α 0 in well-ordered 1 FePt films is investigated by time-resolved magneto-optical Kerr effect. The variation of x mainly affects the electron scattering rate 1/τ e , while other leading parameters remain unchanged. The experimentally observed linear dependence of α 0 on 1/τ e indicates that spin relaxation is through electron interband transitions, as predicted by spin-orbit coupling torque correlation model. Measurements at low temperature show that α 0 remains unchanged with temperature even for FePt with very high chemical order, indicating that electron-phonon scattering is negligible. Moreover, as x decreases the perpendicular magnetic anisotropy increases and the Landau g factor exhibits a negative shift due to an increase in orbital momentum anisotropy. Our results will facilitate the design and exploration of new magnetic alloys with large magnetic anisotropy and desirable damping properties.PACS numbers: 75.78. Jp, 75.70.Tj, 75.50.Vv, 75.30.Gw + e-mail: hbzhao@fudan.edu.cn *e-mail: gxluep@wm.edu.[2] IntroductionUltrafast magnetization precessional switching in ferromagnets utilizing magnetic field pulses, spin polarized currents, and ultrafast laser pulses [1][2][3][4][5][6] is currently a popular topic due to its importance in magnetic information storage and spintronic applications. The uniform magnetization precession can be well modeled with Landau-Lifshitz-GilbertSlonczewski (LLGS) equation [7][8][9], where the Slonczewski torque term denotes the spin transfer torques (STTs), and the Gilbert damping parameter α determines the spin relaxation time [10] and is crucial for device performance [11][12][13][14]. The extrinsic Gilbert damping is due to nonlocal spin relaxation, such as spin pumping and magnon-magnon scattering, which can be tuned by artificial substrates, specially designed buffer and coverage layers [15][16][17][18][19][20][21], while the intrinsic Gilbert damping parameter α 0 is thought to arise from spin-orbit interaction (SOI) [22][23][24][25][26][27][28][29][30], and recently its quadratic dependence on SOI is demonstrated experimentally in FePtPd alloys [31].The α 0 describes the energy flow rate from spin to electronic orbital and phonon degrees of freedom through electron scattering, and has been studied in various theoretical models [22][23][24][25][26][27][28][29][30]. The breathing Fermi surface model [22] and torque-correlation model [23] based on first principle band structure calculations qualitatively match α 0 in soft magnetic alloys such as Fe, . Moreover, contributions to α 0 can be categorized based on intraband and interband transitions [23,26]. The damping rate from intraband transitions scales linearly with the electron relaxation time τ e and exhibits conductivity-like behavior. In contrast, the damping rate from the interband transition is proportional to the electron scattering rate 1/τ e , and consequently exhibits resistivity-like behavior. Therefore, the transition from conductivity-like to re...

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Role of antisite disorder on intrinsic Gilbert damping inL10FePt films

et al. 2015

Phys. Rev. B

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“…The magnetic properties of the (2 × 1) FePt/Pt(111) clusters have been recently studied both experimentally and theoretically [27,28], showing the presence of a pronounced non-collinear magnetic structure in the system. This structure is governed by the strong DM interactions as well as a specific atomic structure consisting of alternating Fe and Pt chains leading to comparable values of isotropic and DM exchange interactions between neighbouring Fe chains.…”

Section: Introductionmentioning

confidence: 99%

Skyrmion magnetic structure of an ordered FePt monolayer deposited onPt(111)

et al. 2014

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The effect of the Dzyaloshinsky-Moriya interaction on the magnetic structure of an ordered FePt monolayer deposited on Pt (111) surface has been investigated. In the ground state, the pronounced anisotropic geometry of the FePt layer with alternating Fe and Pt chains gives rise to a helimagnetic structure with a strong difference in the helicity period along the chains and perpendicular to them. In the presence of an external magnetic field, the region of stable Skyrmion magnetic structures in the B − T phase diagram has been demonstrated via Monte Carlo simulations using the parameters obtained within first-principles electronic structure calculations. The present study demonstrates clearly that the ratio of the exchange coupling parameters J/D for a deposited magnetic filmbeing of central importance for the formation of Skyrmions -can be manipulated by growing an overlayer of 2-dimensional (2D) compounds with the atoms carrying spontaneous magnetic moments separated by the atoms of non-magnetic elements.

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“…Recent studies on Fe stripes on Pt͑997͒ ͑Ref. 24͒ and FePt surface alloys 25 report on strong correlation between complex magnetic ground states and the details of structural arrangement.…”

Section: Introductionmentioning

confidence: 99%

Structurally driven magnetic state transition of biatomic Fe chains on Ir(001)

2009

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Using first-principles calculations, we demonstrate that the magnetic exchange interaction and the magnetocrystalline anisotropy of biatomic Fe chains grown in the trenches of the ͑5 ϫ 1͒ reconstructed Ir͑001͒ surface depend sensitively on the atomic arrangement of the Fe atoms. Two structural configurations have been considered which are suggested from recent experiments. They differ by the local symmetry and the spacing between the two strands of the biatomic Fe chain. Since both configurations are very close in total energy they may coexist in experiment. We have investigated collinear ferro-and antiferromagnetic solutions as well as a collinear state with two moments in one direction and one in the opposite direction ͑↑↓↑-state͒. For the structure with a small interchain spacing, there is a strong exchange interaction between the strands and the ferromagnetic state is energetically favorable. In the structure with larger spacing, the two strands are magnetically nearly decoupled and exhibit antiferromagnetic order along the chain. In both cases, due to hybridization with the Ir substrate the exchange interaction along the chain axis is relatively small compared to free-standing biatomic iron chains. The easy magnetization axis of the Fe chains also switches with the structural configuration and is out-of-plane for the ferromagnetic chains with small spacing and along the chain axis for the antiferromagnetic chains with large spacing between the two strands. Calculated scanning tunneling microscopy images and spectra suggest the possibility to experimentally distinguish between the two structural and magnetic configurations.

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Magnetism of FePt Surface Alloys

Cited by 49 publications

References 18 publications

Role of antisite disorder on intrinsic Gilbert damping inL10FePt films

Role of antisite disorder on intrinsic Gilbert damping inL10FePt films

Skyrmion magnetic structure of an ordered FePt monolayer deposited onPt(111)

Structurally driven magnetic state transition of biatomic Fe chains on Ir(001)

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