共查询到20条相似文献,搜索用时 31 毫秒
1.
Ramis Mustafa Öksüzo?lu Mustafa Y?ld?r?mHakan Ç?nar Erwin HildebrandtLambert Alff 《Journal of magnetism and magnetic materials》2011,323(13):1827-1834
A systematic investigation has been done on the correlation between texture, grain size evolution and magnetic properties in Ta/Ni81Fe19/Ir20Mn80/Co90Fe10/Ta exchange bias in dependence of Ta buffer and NiFe seed layer thickness in the range of 2-10 nm, deposited by pulsed DC magnetron sputtering technique. A strong dependence of 〈1 1 1〉 texture on the Ta/NiFe thicknesses was found, where the reducing and increasing texture was correlated with exchange bias field and unidirectional anisotropy energy constant at both NiFe/IrMn and IrMn/CoFe interfaces. However, a direct correlation between average grain size in IrMn and Hex and Hc was not observed. L12 phase IrMn3 could be formed by thickness optimization of Ta/NiFe layers by deposition at room temperature, for which the maximum exchange coupling parameters were achieved. We conclude finally that the coercivity is mainly influenced by texture induced interfacial effects at NiFe/IrMn/CoFe interfaces developing with Ta/NiFe thicknesses. 相似文献
2.
Morgunov R. B. Talantsev A. D. Bakhmet’ev M. V. Granovskii N. V. 《Physics of the Solid State》2020,62(6):1033-1038
Physics of the Solid State - In the NiFe/Ta/IrMn structures, the contributions of two types of exchange interactions at the NiFe/IrMn interface, partially separated by sections of the nonmagnetic... 相似文献
3.
Pashen’kin I. Yu. Sapozhnikov M. V. Gusev N. S. Rogov V. V. Tatarskiy D. A. Fraerman A. A. 《Technical Physics》2019,64(11):1642-1645
Technical Physics - We have developed technology for manufacturing chains of CoFe/Al2O3/NiFe tunnel magnetoresistive (TMR) elements with pinning on the IrMn antiferromagnetic layer. We have studied... 相似文献
4.
TaN underlayers for spin valves were studied, which were deposited directly on top of Si substrates. The experimental results obtained with the TaN underlayer were compared with those obtained with other (Ta, Mo, and MoN) underlayers. The spin valve structure was Si/Underlayer(tÅ)/NiFe(21 Å)/CoFe(28 Å)/Cu(22 Å)/CoFe(18 Å)/IrMn(65 Å)/Ta(25 Å). The TaN underlayer for a spin valve element exhibited good adhesion to the Si substrate. The XRD patterns of the annealed TaN on bare Si substrate at 900 °C showed no Ta silicide phases, which suggests that the TaN layer may also be used as a diffusion barrier between Si substrate and the ensuing spin valve active layers, as well as an underlayer. A spin valve element having TaN underlayer deposited directly on top of a Si substrate showed a high MR ratio of about 8.3% after annealing at 200 °C. It is concluded that it is advantageous to use a TaN underlayer if one wants to fabricate spin valve elements directly on top of Si substrates. 相似文献
5.
G.C. Han P. Luo J.J. Qiu K.B. Li Y.H. Wu 《Applied Physics A: Materials Science & Processing》2002,75(6):655-659
The use of nano-oxide to improve the performance of spin valves has been extensively studied. But most of the investigations
so far have been carried out on different samples. This may make some of the conclusions drawn from the experiments inconsistent
because of the fluctuation in deposition conditions and device structures. In this work, the effect of nano-oxide on the properties
of spin valves has been investigated through post-growth oxidation of the same sample in oxygen plasma for different rf powers
and durations. The sample investigated was a bottom spin valve with the structure Si/SiO2/Ta/NiFe/IrMn/CoFe/Cu/CoFe/Ta. A relative increase of 20% and 12% was obtained in the giant magnetoresistance (GMR) ratio
of as-deposited and annealed samples, respectively. It was found that, at a fixed rf power, there is a peak of the GMR ratio
as the oxidation time increases. A higher peak value of the GMR ratio was obtained for lower rf power, although the required
oxidation time is longer. This result can be well understood by considering both the enhanced specularity at the insulator/metal
interface and the loss of magnetic effective thickness of the free layer by the oxidation. Magnetic parameters such as the
interlayer coupling field (H0) and the coercivity of the free layer (Hcf) were also greatly influenced by the oxidation process. When only the Ta layer was oxidized, H0 increases very slightly, and Hcf increases with the oxidation time. However, when the CoFe free layer was oxidized, a significant increase was found for H0, and Hcf changes to decreasing. These results can be explained based on the Néel and RKKY coupling models.
Received: 25 October 2001 / Accepted: 21 December 2001 / Published online: 3 June 2002 相似文献
6.
《Journal of magnetism and magnetic materials》2001,233(3):164-168
The MR characteristics of temperature variations ranging from room temperature to 570 K for IrMn spin-valves which consist of free layer Co, CoFe and NiFe were studied. Co-SV had the highest MR value in all temperature ranges among them and even at 510 K the MR ratio held more than half of room temperature value. Whereas CoFe-SV had a slightly higher MR than NiFe-SV below 450 K, above 450 K CoFe-SV showed a lower MR ratio than NiFe-SV. MR loops of large coercivity such as CoFe free magnetic layer collapsed in the lower elevated temperature compared to NiFe and Co. Small coercivity of the free magnetic layer would be preferable to spin-valves. 相似文献
7.
利用高分辨电子显微学方法(HREM)研究了纳米氧化层镜面反射自旋阀多层结构Ta(35nm)Ni80Fe20(2nm)Ir17Mn83(6nm)Co90Fe10(15nm)NOL1Co90Fe10(2nm)Cu(22nm)Co90Fe10(15nm)NOL2Ta(3nm).该自旋阀的巨磁电阻(GMR)效应高达15%,较无此镜面反射纳米氧化层(NOL)的自旋阀提高近1倍,同时交换偏置场亦有所增强.高分辨显微结构分析表明,介于钉扎层与被钉扎层之间的氧化层(NOL1)并未完全氧化,即除氧化过程生成的CoFe氧化物
关键词:
自旋阀
纳米氧化层
高分辨电子显微学
巨磁电阻效应 相似文献
8.
The effect of the antiferromagnetic IrMn thickness upon the magnetic properties of CoFe/Pt/CoFe/[IrMn(tIrMn)] multilayers is studied. An oscillatory interlayer coupling (IEC) has been shown in pinned CoFe/Pt(tPt)/CoFe/IrMn multilayers with perpendicular anisotropy. The period of oscillation corresponds to about 2 monolayers of Pt. The oscillatory behavior of IEC depends on the nonmagnetic metallic Pt thickness and is thought to be related to the antiferromagnetic ordering induced by the IrMn layer. From the extraordinary Hall voltage amplitude (EHA) curves as function of IrMn thickness, we report that the oscillation dependence of IEC for the [CoFe/Pt/CoFe] multilayer system induced by IrMn with spacer-layer thickness is a important features of perpendicular exchange biased system. 相似文献
9.
Physics of the Solid State - In a series of NiFe/Cu/IrMn structures with a variable effective thickness of the nonmagnetic copper interlayer (up to its absence in the NiFe/IrMn sample), we observed... 相似文献
10.
Yong-Goo Yoo Seong-Gi Min Ho-Jun Ryu Nam-Seok Park Seong-Cho Yu 《Journal of magnetism and magnetic materials》2006
Exchange biased IrMn/NiFe/IrMn thin films were studied as a function of NiFe thickness. In plane angular dependence of a resonance field distribution which is measured by FMR was analyzed as a combined effect of an unidirectional anisotropy and an uniaxial anisotropy. The unidirectional anisotropic field and the uniaxial anisotropic field were linearly varied with NiFe thickness while the films with a thicker NiFe layer do not follow the linear variation. Resonance field and linewidth variations were also analysed with NiFe thickness. 相似文献
11.
Flexible tuning microwave permeability spectrum in [ferromagnet/antiferromagnet]_n exchange-biased multilayer stack structure
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NiFe/[IrMn/NiFe/IrMn] 5 /[NiFe/IrMn] 4 /NiFe structured exchange-biased multilayer films are designed and prepared by magnetron sputtering. The static and the microwave magnetic properties are systematically investigated. The results reveal that adding a partially pinned ferromagnetic layer can effectively broaden the ferromagnetic resonance linewidth toward the low frequency domain. Moreover, a wideband multi-peak permeability spectrum with a 3.1-GHz linewidth is obtained by overlapping the spectra of different partially pinned ferromagnetic layers and [antiferromagnet/ferromagnet/antiferromagnet] n stacks. Our results show that the linewidth of the sample can be feasibly tuned through controlling the proper exchange bias fields of different stacks. The designed multilayered thin films have potential application for a tunable wideband high frequency noise filter. 相似文献
12.
Influence of Ga+ ion irradiation on thermal relaxation of exchange bias field in exchange-coupled CoFe/IrMn bilayers
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This paper reports that the CoFe/IrMn bilayers are deposited by magnetron sputtering on the surfaces of thermallyoxidized Si substrates.It investigates the thermal relaxations of both non-irradiated and Ga + ion irradiated CoFe/IrMn bilayers by means of holding the bilayers in a negative saturation field.The results show that exchange bias field decreases with the increase of holding time period for both non-irradiated and Ga + ion irradiated CoFe/IrMn bilayers.Exchange bias field is also found to be smaller upon irradiation at higher ion dose.This reduction of exchange bias field is attributed to the change of energy barrier induced by ion-radiation. 相似文献
13.
Martí X Park BG Wunderlich J Reichlová H Kurosaki Y Yamada M Yamamoto H Nishide A Hayakawa J Takahashi H Jungwirth T 《Physical review letters》2012,108(1):017201
We employ antiferromagnetic tunneling anisotropic magnetoresistance to study the behavior of antiferromagnetically ordered moments in IrMn exchange coupled to NiFe. Experiments performed by common laboratory tools for magnetization and electrical transport measurements allow us to directly link the broadening of the NiFe hysteresis loop and its shift (exchange bias) to the rotation and pinning of antiferromagnetic moments in IrMn. At higher temperatures, the broadened loops show zero shift, which correlates with the observation of fully rotating antiferromagnetic moments inside the IrMn film. The onset of exchange bias at lower temperatures is linked to a partial rotation between distinct metastable states and pinning of the IrMn antiferromagnetic moments in these states. The observation complements common pictures of exchange bias and reveals an electrically measurable memory effect in an antiferromagnet. 相似文献
14.
Z. M. Zeng Y. Wang X. F. Han W. S. Zhan Z. Zhang 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(2):205-208
Bias voltage and temperature dependence of
magneto-electric properties in double-barrier magnetic tunnel
junctions(DBMTJs) with a structure of [IrMn/CoFe/Ru/CoFeB]/Al-O/CoFeB/Al-O/[CoFeB/Ru/CoFe/IrMn], have been investigated. The
DBMTJs show a large tunnel magnetoresistance (TMR) ratio of up to
57.6%, a high V1/2 value of 1.26 V and small switching field
Hc of 9.5 Oe at room temperature (RT). The TMR reaches the
maximum at 30 K, about 89.0%, and decreases slightly from 30 to 4.2
K. A novel zero-bias anomaly (ZBA) in the P state is found and is
temperature dependent, more sharply at low temperature, whereas a
normal ZBA exists in the AP state. These effects are ascribed to
magnon-, phonon- and impurity-assisted tunneling, and variation of
density of states. The DBMTJ with a large TMR ratio, a high
V1/2, and small switching field Hc is promising for
developing the future spin electronic devices. 相似文献
15.
Growth and characterization of silicon nitride films on various underlying materials 总被引:3,自引:0,他引:3
G.C. Han P. Luo K.B. Li Z.Y. Liu Y.H. Wu 《Applied Physics A: Materials Science & Processing》2002,74(2):243-247
Characteristics of silicon nitride (SiNx:H) films, grown by plasma enhanced chemical vapor deposition (PECVD) on various metals such as Ta, IrMn, NiFe, Cu, and CoFe
at various temperatures down to 100 °C, were studied using measurements of BHF etch rate, surface roughness and Auger electron
spectroscopy (AES). The results were compared with those obtained for SiNx:H films on Si. The deposition rate of SiNx:H films increased slightly as deposition temperature decreased, and showed a weak dependence on the underlying materials.
The surface of the nitride films deposited on all underlying materials at lower temperatures (below 150 °C) became rougher.
In particular, a bubble-like surface was observed on the nitride film deposited on NiFe at 100 °C. At higher deposition temperatures
(above 200 °C), SiNx:H films on all the above metals had small RMS values, except for films on Cu which cracked at 250 °C. BHF (10:1) etch rate
increased dramatically for nitride films deposited below 150 °C. For different underlying films, the BHF etch rate was quite
different, but exhibited the same trend with decrease in deposition temperature. AES measurements showed that Si and N concentrations
in the SiNx:H films were only slightly different for the various deposition temperatures and underlying materials. AES depth profile
of nitride films indicated that both surface O content and the depth of oxygen penetrating into SiNx:H increased for low temperature-deposited films. However, there was no observed oxygen signal from within the films, even
for films deposited at 100 °C, and both Si and N concentrations were uniform throughout the film.
Received: 26 October 2001 / Accepted: 2 March 2001 / Published online: 20 June 2001 相似文献
16.
H. Sakakima M. Satomi Y. Sugita Y. Kawawake 《Journal of magnetism and magnetic materials》2000,210(1-3)
Spin valves having thin oxide layers in the pinned and/or free layers were prepared by sputtering. MR ratios of the spin valves were increased from 8.1 to 11.9% by inserting the oxide layer into the pinned layer in Ta/PtMn/CoFe/Cu/CoFe/Ta spin valves. MR ratio of 13.9% and considerably large sheet ΔR of 2.55 Ω were obtained in the PtMn-based spin valves having the oxide layer in the pinned and free layer. Larger MR ratio of 17.3% and the sheet ΔR of 1.3 Ω were obtained in the PtMn-based dual-type spin valves having the oxide layer in both pinned layers. α-Fe2O3 based spin valves having thin oxide layers were also prepared. MR ratios of the spin valves were increased from 11.9 to 14.3% by inserting the oxide layer into the free layer in α-Fe2O3/CoFe/Cu/CoFe/Ta spin valves. The enhancement of the MR ratios may be attributed to the specular scattering effect of the conduction electrons by the thin oxide layers. 相似文献
17.
This paper reports that a CoFe/IrMn bilayer was deposited by high vacuum magnetron sputtering on silicon wafer
substrate; the thermal relaxation of the CoFe/IrMn bilayer is investigated by means of holding the film in a negative saturation field at various temperatures. The exchange bias decreases with increasing period of time while holding the film in a negative saturation field at a given temperature. Increasing the temperature accelerates the decrease of exchange field. The results can be explained by the quantitative model of the nucleation and growth of antiferromagnetic domains suggested by Xi H W et al. [2007 Phys. Rev. B 75 014434], and it is believed that two energy barriers exist in the
investigated temperature range. 相似文献
18.
F. Russo G. Carapella V. Granata N. Martucciello G. Costabile 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(1):61-66
The magnetoresistance of several Ferromagnet/Normal
metal/Ferromagnet spin-valve type structures has been investigated using Al
as normal spacer layer. A magnetoresistance ratio up to 4.1% at room
temperature and 5.7% at 0.3 K is found for the sandwich with both Co
layers, while slightly lower signals are found for the structures involving
CoFe and NiFe layers. The magnetoresistance dependence for Co/Al/Co,
Co/Al/CoFe and Co/Al/NiFe on the spacer layer thickness exhibits the
familiar non monotonic behaviour with second peak slightly larger than the
one reported for Cu based pseudo spin valves. At cryogenic temperatures,
preliminary results on the onset of spin switch effects in Co/Al/Co and the
full spin switch effect in Co/Nb/Co are also reported here. 相似文献
19.
20.
文章中,通过磁控溅射制备了界面处插入4d,5d元素薄层(包括Ru,Pd,Ag和Au)的Ta/NiFe/Ta多层膜,并对它们的磁输运和磁性以及微结构进行了测试和表征.结果显示,Pd和Pt一样界面效应显著,能有效地提高NiFe薄膜退火前后的AMR比值,并抑制磁性死层.表面能比较小、熔点相对低的插层材料Ag,Au在退火过程中容易通过晶界扩散,强烈破坏其AMR性能.对于熔点高、表面能比较大的插层材料如Ru,磁性死层同样得到了抑制,NiFe薄膜的温度稳定性也可以得到提高.结果表明界面插层从界面电子自旋-轨道散射、界面死层和界面原子扩散等方面深刻影响NiFe薄膜的AMR.
关键词:
各向异性磁电阻
界面效应
原子扩散 相似文献