亚洲免费av电影一区二区三区,日韩爱爱视频,51精品视频一区二区三区,91视频爱爱,日韩欧美在线播放视频,中文字幕少妇AV,亚洲电影中文字幕,久久久久亚洲av成人网址,久久综合视频网站,国产在线不卡免费播放

        ?

        Enhanced spin-orbit torque efficiency in Pt100?xNix alloy based magnetic bilayer?

        2021-03-19 03:19:38CongliHe何聰麗QingqiangChen陳慶強(qiáng)ShipengShen申世鵬JinwuWei魏晉武HongjunXu許洪軍YunchiZhao趙云馳GuoqiangYu于國強(qiáng)andShouguoWang王守國
        Chinese Physics B 2021年3期
        關(guān)鍵詞:趙云魏晉

        Congli He(何聰麗), Qingqiang Chen(陳慶強(qiáng)), Shipeng Shen(申世鵬), Jinwu Wei(魏晉武), Hongjun Xu(許洪軍),Yunchi Zhao(趙云馳), Guoqiang Yu(于國強(qiáng)), and Shouguo Wang(王守國),?

        1Institute of Advanced Materials,Beijing Normal University,Beijing 100875,China

        2Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

        Keywords: spin-orbit torque,magnetic doping,spin-torque ferromagnetic resonance

        Spin-orbit torque (SOT) has been widely employed for driving magnetization switching,[1-8]magnetization oscillation,[9-12]domain wall motion,[13-15]and skyrmion motion,[16-19]exhibiting promising potentials in spintronic device applications.A typical SOT sample has a bilayer structure consisting of heavy metal(HM)/ferromagnetic metal(FM).In general, the HMs are chosen from 5d elements, such as Ta,W, and Pt.[1-7,9-21]When passing an electrical current in the HM/FM,it generates an out-of-plane spin current due to spin Hall effect and/or Rashba effect.The spin current diffuses into the adjacent FM layer and exerts torques, i.e., the SOTs, acting on the magnetization of FM.To reduce the electrical current density for magnetization manipulation and hence lower the power consumption,it is essential to enhance the SOT efficiency (ξDL), which has become one important goal in the study and application of SOT.

        In this work,the magnetic properties and SOT efficiency in Pt100?xNix/ Ni78Fe22(NiFe) bilayers were studied by spintorque ferromagnetic resonance (ST-FMR) technique.[37-40]The effective anisotropy field and effective damping constant(αeff)were obtained via analyzing the ST-FMR spectra.The effective spin-mixing conductance and the interfacial spin transparency were further extracted. The results show that the SOT efficiency can be enhanced by doping the magnetic Ni into Pt,and it reaches the maximum value when x=18.These results may be useful for designing and developing SOT-driven spintronic devices.

        Two series of multilayer stacks were prepared:(I) Pt100?xNix(6)/NiFe(5)/MgO(2)/Pt(2) (thicknesses in nm) with x = 0, 6, 12, 18, and 30, respectively;(II)Pt70Ni30(6)/NiFe(t)/MgO(2)/Pt(2)with t =2, 3.5, 5, 6.5,and 8,respectively.All the stacks were deposited on thermally oxidized Si substrates by magnetron sputtering tool in a vacuum of less than 5×10?8Torr and at Ar pressure of 3 mTorr at room temperature. The composition of Pt100?xNixwas tuned by co-sputtering Pt and Ni under different powers. The multilayers were then patterned into Hall bars and rectangular strips by UV lithography and Ar ion milling for typical fourpoint resistance measurements and ST-FMR measurements,respectively. The contact electrodes with Cr/Au were used for electrical measurements.

        The schematic of the devices for ST-FMR measurements and the coordinates are illustrated in the inset of Fig.1(a). The details for ST-FMR measurement can be found in our previous work.[37,38,40]The power of the microwave used for this measurement is 13 dBm. Figure 1(a) shows the ST-FMR spectra for the Pt100?xNix(6)/NiFe(5) sample with x=18 under the frequency of 9.0 GHz. The results can be well fitted by a sum of symmetric and antisymmetric Lorentzian functions

        where ΔH is the linewidth,H0is the resonant magnetic field,S is the symmetric Lorentzian coefficient,and A is the antisymmetric Lorentzian coefficient. Figure 1(b) presents the resonance frequency f as a function of the resonant fieldμ0H0for different samples. The results for different samples are quite identical, and they can be well fitted by the Kittel equation f =(γ/2π)[μ0H0(μ0H0+4πMeff)]1/2(γ is the gyromagnetic ratio and μ0is the vacuum permeability). The effective magnetization fields (4πMeff) for different samples are extracted from the fitting,[38]as shown in Fig.1(d), which exhibit a weak dependence on the Ni concentration. Figure 1(c)shows the frequency dependence of resonance linewidth ΔH for the samples with various Ni concentrations. The results can be linearly fitted by ΔH =ΔH0+(2παeff/γ)f, based on which the effective damping constants are thus obtained, as shown in Fig.1(d). Similar to the effective magnetization field, the effective damping constant also exhibits a weak dependence on the Ni concentration,indicating that the Ni doping does not have an obvious influence on the magnetic properties of the adjacent NiFe layer.

        Fig.1. (a)ST-FMR spectrum for Pt100?xNix(6 nm)/NiFe(5 nm)/MgO(2 nm)/Pt(2 nm)with x=18 under the frequency of 9.0 GHz,which is fitted to a Lorentzian function consisting of a symmetric and an antisymmetric Lorentzian component(the solid curves). Inset: schematic of a Pt100?xNix/NiFe device for ST-FMR measurements. (b)Resonance frequency f versus the resonant fieldμ0H0 for Pt100?xNix/NiFe devices,which can be well fitted to the Kittel equation.(c)The linewidth as a function of the resonance frequency f,which can be linearly fitted.(d)The effective damping constant αeff determined by the linear fitting,and the effective magnetization fields 4πMeff for Pt100?xNix/NiFe devices with different Ni contents.

        The Pt70Ni30/NiFe(t) samples with different thicknesses of NiFe layer were also measured for investigating the interfacial spin transmission. Figure 2(a) shows the resonance frequency f as a function of the resonant field μ0H0. These results can also be well fitted by the Kittel equation. Figure 2(b) shows the effective magnetization fields 4πMefffor the Pt70Ni30/NiFe(t) devices, which decrease from 0.910±0.023 T to 0.349±0.004 T as the thickness of the NiFe layer decreases from 8.0 nm to 2.0 nm, reflecting the gradual increasing contribution of the interfacial anisotropy with decreasing thickness.Figure 2(c)shows the linewidth ΔH versus the resonance frequency f for different samples,which allows us to extract the αeffvalues for different samples. The αeffas a function of tNiFeis given in the inset of Fig.2(d),which increases from 0.017 to 0.104 as the NiFe thickness decreases from 8.0 nm to 2.0 nm.

        Based on the previous studies,[40,41]the damping can be approximately given by

        Here, tHM, λHM, and ρHMare the thickness, spin-diffusion length, and resistivity of the HM layer (here is the Pt70Ni30layer), respectively. We note that the spin diffusion length of pure Pt (λPt= 1.9 nm) is used for estimating the interfacial spin transparency.[25]Tin≈0.59 was obtained for the Pt70Ni30/NiFe interface.

        Fig.2. (a)Resonance frequency f as a function of the resonant fieldμ0H0 for Pt70Ni30/NiFe devices with different thicknesses of NiFe layer.(b) The effective magnetization fields 4πMeff for Pt70Ni30/NiFe devices plotted as a function of the NiFe thickness. (c) The linewidth ΔH versus the resonance frequency f for Pt70Ni30/NiFe devices with different thicknesses of NiFe layer. (d) The effect damping constant αeff plotted as a function of and fitted by Eq.(2)(the solid curve). Inset: effective damping constant as a function of tNiFe.

        Fig.3. (a)Angular dependence of symmetric and antisymmetric components for Pt100?xNix/NiFe devices with x=18,which are mainly dependent on angle relation of cosφ sin2φ. (b) The values of SOT efficiency ξSOT and resistivity ρHM as a function of Ni content.

        Next, we turn to analyze and discuss the SOT efficiency of the samples. The SOT efficiency can be quantitatively determined from the ratio between the symmetric(Vs)and antisymmetric(Va)components of the resonance curve,which are expressed as[40]

        Figure 3(a) shows the angular dependence of the Vsand Vacomponents for the Pt100?xNix/NiFe devices with x = 18,which can be fitted well to cos? sin2?. A quantity ξSOTcan be estimated from the Vs/Varatio,[44]

        In summary,the magnetic properties and SOT efficiency of Pt100?xNix/NiFe bilayers were studied by ST-FMR. The effective anisotropy field and effective damping constant exhibit a weak dependence on the Ni concentration. The effective spin-mixing conductance and the interfacial spin transparency were extracted for the Pt70Ni30/NiFe. The SOT efficiency can be beneficially enhanced by adding scattering centers to increase the electrical resistivity of the HM,which increases with the Ni concentration and reaches the maximum value when x =18. Our results indicate that the SOT efficiency can be tuned by doping Ni. Considering the low cost of Ni compared to Pt and the enhanced SOT efficiency in Pt100?xNix/NiFe,this study may help to reduce the cost of the SOT devices.

        猜你喜歡
        趙云魏晉
        A NOTE ON MEASURE-THEORETICEQUICONTINUITY AND RIGIDITY*
        《無風(fēng)的夏日》
        人文天下(2021年6期)2021-12-05 00:37:40
        魏晉士人的“身名俱泰”論
        原道(2020年2期)2020-12-21 05:47:10
        標(biāo)點(diǎn)符號(hào)的爭吵
        魏晉清談探析
        Jokes Today
        甘南牧民 趙云雁
        金秋(2020年4期)2020-08-18 02:39:20
        沒落期|魏晉南北朝至唐代
        SUB-ADDITIVE PRESSURE ON A BOREL SET?
        魏晉風(fēng)流,縱是靜坐也繁華……
        火花(2015年7期)2015-02-27 07:44:01
        伊甸园亚洲av久久精品| 久久国产精品一区二区| 蜜桃成熟时日本一区二区| 久久久精品中文字幕麻豆发布| 欧美xxxx色视频在线观看 | 国产精品无码久久综合| 97午夜理论片在线影院| 欧美日韩国产在线成人网| 在线观看视频国产一区二区三区| 国产精品黄色片在线看| 久久99久久99精品中文字幕| 精品视频999| 精品人妻久久av中文字幕| 美女用丝袜脚玩我下面| 成l人在线观看线路1| 亚洲综合国产精品一区二区99| 亚洲蜜桃视频在线观看| 日韩精品视频久久一区二区 | 亚洲中文字幕第15页| 先锋中文字幕在线资源| 无码人妻丰满熟妇精品区| 久久91精品国产91久久麻豆| 91国产精品自拍在线观看| 一本色道久久88精品综合| 在线亚洲综合| 亚洲av一区二区网址| 麻豆文化传媒精品一区观看| av在线亚洲欧洲日产一区二区| 91国在线啪精品一区| 中文字幕人妻被公喝醉在线| 中国女人内谢69xxxxxa片| 国产精品va在线播放我和闺蜜| 久久国产精品超级碰碰热| 亚洲免费女女在线视频网站| 一本色道久久综合无码人妻| 亚洲红怡院| 国产三级c片在线观看| 日本真人边吃奶边做爽动态图| 人妻精品无码一区二区三区| 午夜一区二区三区在线视频| 夜晚黄色福利国产精品|