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1.
J. Fassbender S. Poppe T. Mewes J. Juraszek B. Hillebrands K.-U. Barholz R. Mattheis D. Engel M. Jung H. Schmoranzer A. Ehresmann 《Applied Physics A: Materials Science & Processing》2003,77(1):51-56
It has been demonstrated that He+ ion irradiation is an excellent tool for modifying magnetic properties, like the magnetic anisotropy, the interlayer exchange
coupling strength and the exchange bias field of ultra-thin magnetic layered systems. This paper summarizes the effects of
ion irradiation on exchange bias systems. As a first example, for possible applications of the ion induced magnetic effects,
the realization of an angle sensing device is described.
Received: 11 November 2002 / Accepted: 12 November 2002 / Published online: 4 April 2003
RID="*"
ID="*"Corresponding author. Fax: +49-631-205-4095, E-mail: fassbend@physik.uni-kl.de
RID="**"
ID="**"Present address: Université de Rouen, Rouen, France 相似文献
2.
C. Teichert 《Applied Physics A: Materials Science & Processing》2003,76(5):653-664
Spontaneous pattern formation during epitaxial growth or ion erosion of semiconductor wafers offers an elegant route towards
large-area nanostructured surfaces. In homoepitaxy, kinetics may result in rather uniform three-dimensional islands. In the
case of semiconductor heteroepitaxy, strain relief leads to the formation of nanofaceted three-dimensional crystallites, which
may self-organize into quasiperiodic arrays. By tuning substrate miscut and film thickness, or growing superlattices, a variety
of patterns with different symmetries can be obtained, as will be summarized for the model system of SiGe on Si(001). Since
these self-organized nanostructure arrays cover the entire wafer on which they are grown, they can serve as large-area nanopatterned
substrates for subsequent deposition of magnetic thin films. It will be demonstrated that such templates allow the study of
correlations between magnetic and chemical interfacial roughness, as well as the influence of pattern symmetry on the magnetic
anisotropy of thin Co films. Furthermore, shadow deposition of magnetic material onto specially faceted nanostructure arrays
allows the fabrication of nanomagnet arrays and the study of their magnetic properties.
Received: 31 July 2002 / Accepted: 2 October 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +43-3842/402-760, E-mail: teichert@unileoben.ac.at 相似文献
3.
S.A. Nepijko M. Klais G. Schönhense N. Cramer Z. Celinski C.M. Schneider S. Zennaro N. Zema N.N. Sedov 《Applied Physics A: Materials Science & Processing》2003,76(5):809-815
Micromagnetic properties of the Fe19Ni81 (5 nm)/NiO (50 nm)/Fe19Ni81 (30 nm) structured system have been investigated in a photoemission electron microscope in the magnetic X-ray circular dichroism
operating mode. The microstructured Fe19Ni81 (5 nm) film contained two-dimensional islands with the aspect ratio varying from 1:1 to 10:1, and the linear size of their
long axis comprised 24, 12 and 6 μm. It is shown that the magnetic domains have the direction of magnetization preferentially
parallel and antiparallel to the magnetic field direction in which this system was prepared. Their number is determined by
the particles’ sizes, their shape as well as by the direction of the external magnetizing field and can be characterized by
a non-monotonic size dependence. The magnetization of domains with different lateral sizes was found to be 0.4 T with an accuracy
better than 20%.
Received: 29 May 2002 / Accepted: 17 July 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +49-6131/392-3807, E-mail: nepijko@mail.uni-mainz.de 相似文献
4.
A. Krasyuk A. Oelsner S.A. Nepijko A. Kuksov C.M. Schneider G. Schönhense 《Applied Physics A: Materials Science & Processing》2003,76(6):863-868
Owing to its parallel image acquisition, photoemission electron microscopy is well suited for real-time observation of fast
processes on surfaces. Pulsed excitation sources like synchrotron radiation or lasers, fast electric pulsers for the study
of magnetic switching, and/or time-resolved detection can be utilised. A standard approach also being used in light optical
imaging is stroboscopic illumination of a periodic (or quasi-periodic) process. Using this technique, the time dependence
of the magnetic field in a pulsed microstrip line has been imaged in real time exploiting Lorentz-type contrast. Similarly,
the corresponding field-induced changes in the magnetisation of cobalt microstructures deposited on the microstrip line have
been observed exploiting magnetic X-ray circular dichroism as a contrast mechanism. The experiment has been performed at the
UE 56/1-PGM at BESSY II (Berlin) in the single-bunch mode.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-6131/392-3807, E-mail: krasyuk@mail.uni-mainz.de 相似文献
5.
J. Fortágh H. Ott S. Kraft A. Günther C. Zimmermann 《Applied physics. B, Lasers and optics》2003,76(2):157-163
In this article, we describe an experimental system for generating Bose–Einstein condensates and controlling the shape and
motion of a condensate by using miniaturised magnetic potentials. In particular, we describe the magnetic trap setup, the
vacuum system, the use of dispenser sources for loading a high number of atoms into the magneto-optical trap, the magnetic
transfer of atoms into the microtrap, and the experimental cycle for generating Bose–Einstein condensates. We present first
results on outcoupling of condensates into a magnetic waveguide and discuss influences of the trap surface on the ultra-cold
ensembles.
Received: 21 August 2002 / Revised version: 10 December 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-7071/295-829, E-mail: fortagh@pit.uni-tuebingen.de 相似文献
6.
M. Dreyer M. Kleiber R. Wiesendanger 《Applied Physics A: Materials Science & Processing》1999,69(3):359-361
We have applied magnetic force microscopy in ultrahigh vacuum to study the correlation between the atomic step and magnetic
domain wall structure of ultrathin Co films prepared in situ on Au(111) substrates. For the first time we were able to achieve
high-resolution images showing simultaneously a clear domain wall contrast and the underlying atomic step structure. Although
for in-plane magnetized Co films the domain walls were found to run preferentially in a direction perpendicular to the steps,
no such correlation could be observed for out-of-plane magnetized Co films.
Received: 3 June 1999 / Accepted: 4 June 1999 / Published online: 29 July 1999 相似文献
7.
Ta/NiOx/Ni81Fe19/Ta films were prepared by rf reactive and dc magnetron sputtering. The exchange coupling field Hex and the coercivity Hc of NiOx/Ni81Fe19 as a function of the ratio of Ar to O2 during the deposition process were studied. The composition and the chemical states in the interface region of NiOx/NiFe were also investigated using X-ray photoelectron spectroscopy (XPS) and the peak decomposition technique. The results
show that the ratio of Ar to O2 has a great effect on the chemical states of nickel in NiOx films. The exchange coupling field Hex and the coercivity Hc of Ta/NiOx/Ni81Fe19/Ta are thus seriously affected. XPS is shown to be a powerful tool for characterizing magnetic films.
Received: 18 July 2001 / Accepted: 21 December 2001 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-010/6232-7283, E-mail: guanghua_yu@263.net 相似文献
8.
R. Frömter H.P. Oepen J. Kirschner 《Applied Physics A: Materials Science & Processing》2003,76(6):869-871
The basics of the scanning electron microscope with polarization analysis are briefly reviewed, emphasizing the achievable
magnetic resolution and image contrast. The design of an optimized spin-polarization detector based on the well-established
LEED scattering principle is presented. Results of first tests are reported.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-40/42838-6368, E-mail: RFroemte@PHYSnet.Uni-Hamburg.de 相似文献
9.
The present work discusses the successful electrodeposition of Cu/Co multilayers, exhibiting appreciable GMR of 12-14% at room temperature. The effect of individual Cu and Co layers on the magnitude and behavior of GMR has been studied. By varying the thickness of individual layers the field at which saturation in GMR is observed can be controlled. It was observed that for lower thicknesses of Co layer, the saturation fields are reduced below 1 kOe. The Cu layer thickness seems to control the nature of magnetic coupling and the saturation field, with the two showing a correlation. 相似文献
10.
P. Prod’homme F. Maroun R. Cortès P. Allongue J. Hamrle J. Ferré J.-P. Jamet N. Vernier 《Journal of magnetism and magnetic materials》2007
Au/Co(4–8 ML)/Au single magnetic layers and Au(8 ML)/Co(4 ML)/Au(8 ML)/Co(8 ML)/Au bilayer were sequentially grown by electrodeposition on an Au(1 1 1) buffer layer electrodeposited on Si(1 1 1). The technique used in this work provides full control on the structure and the chemical composition of the different layers (no alloying) as well as on the chemistry at interfaces. scanning tunneling microscopy (STM) and atomic force microscopy (AFM) imaging and X-ray diffraction measurements show that atomically flat continuous Co(0 0 0 1) layers (4–8 ML) can be grown in epitaxy with the Au(1 1 1) substrate and that the 2 nm-thick spacer is also a continuous Au(1 1 1) layer. The Co ultrathin layers (4 and 8 ML) exhibit perpendicular magnetic anisotropy. The lateral magnetic homogeneity and magnetization reversal process have been investigated by scanning magneto-optical Kerr effect (MOKE) magnetometry and global Kerr microscopy. The correlation between magnetization switching behaviour in each layer of the Co-bilayer stack has been evidenced from in-depth sensitive MOKE measurements and microscopy. The strong coupling observed between the two Co layers is attributed to magnetostatic interaction at domain wall boundaries. 相似文献
11.
J. Vogel W. Kuch K. Fukumoto F. Romanens S. Pizzini J. Camarero 《Applied Physics A: Materials Science & Processing》2008,92(3):505-510
We have used time-resolved x-ray magnetic circular dichroism combined with photoemission electron microscopy (XMCD-PEEM) to
investigate the layer-resolved microscopic magnetization reversal in FeNi/X/Co (with X=Cu, Al2O3) trilayer systems. These measurements were performed in pump-probe mode, synchronizing magnetic pulses with synchrotron x-ray
pulses. The good magnetic contrast observed for most samples reveals that in many cases the magnetization reversal is reproducible.
We have used the measurements to obtain domain wall propagation speeds as a function of applied magnetic field, and to investigate
the influence of domain wall interactions on the magnetic switching. 相似文献
12.
Electromodulation of the magnetoresistance in diluted magnetic semiconductors based heterostructures
We study the properties of heterostructures formed by two layers of a diluted magnetic semiconductor separated by a nonmagnetic semiconductor layer. We find that there is a RKKY-type exchange coupling between the magnetic layers that oscillates between ferromagnetic and antiferromagnetic as a function of the different parameters in the problem. The different transport properties of these phases make that this heterostructure presents strong magnetoresistive effects. The coupling can be also modified by an electric field. We propose that it is possible to alter dramatically the electrical resistance of the heterostructure by applying an electric field. Our results indicate that in a single gated sample the magnetoresistance could be modulated by an electrical bias voltage. 相似文献
13.
The coercivity of a Co/Pt multilayer with out-of-plane anisotropy can be lowered greatly if it is grown onto an ultrathin NiO underlayer . By making use of this characteristic, a series of samples glass/NiO(10 Å)/[Co(4 Å)/Pt(5 Å)]3/Pt(x Å)/[Co(4 Å)/Pt(5 Å)]3 with different Pt spacer thickness have been prepared to determine the ferromagnetic (FM) coupling between Co layers across the Pt layer. The measurements of major and minor hysteresis loops have shown that the FM coupling between the top and bottom Co/Pt multilayers decreases monotonically with the Pt layer thickness and disappears above the Pt layer thickness of 40 Å. This thickness of 40 Å is much larger than that in the literature. In addition to the FM coupling between the top and bottom Co/Pt multilayers across the Pt spacer, there exists a weak biquadratic coupling, which induces the broad transition of the bottom Co/Pt multilayer. 相似文献
14.
E.E. Shalygina G.V. Maximova V.A. Melnikov V.V. Molokanov 《Journal of magnetism and magnetic materials》2009,321(7):865-867
Results on the investigation of the magnetic properties of nanocrystalline Co/Ni/Fe and Fe/Zr/Fe thin-film systems are presented. The study of the magnetic properties of the examined samples was carried out employing magneto-optical micromagnetometer with a surface sensitivity about of 20 nm of the thickness depth and a vibrating sample magnetometer. The examined samples were revealed to exhibit hysteresis loops of complicated forms. These data were explained by the magnetostatic and exchange interactions between the layers in heterogeneous magnetic materials. 相似文献
15.
M.R. Koblischka B. Hewener U. Hartmann A. Wienss B. Christoffer G. Persch-Schuy 《Applied Physics A: Materials Science & Processing》2003,76(6):879-884
Microstructured thin-film elements with critical dimensions of 1 μm or less play an increasingly important role in magnetic
components for information technology applications. Devices that are directly based on such microstructures are key components
in magnetoelectronics for storage and sensor applications as well as modern concepts which are likely to substitute today’s
hard disk drives. Basic research on magnetic materials as well as industrial applications create an increasing demand for
high-resolution magnetic imaging methods. One such method is magnetic force microscopy (MFM). In spite of considerable achievements,
MFM also has some serious shortcomings, which have not been overcome to date. Under normal circumstances, the method yields
only qualitative information about the magnetic object and it is difficult to improve the resolution to values below 100 nm.
In this paper, we will report on advanced MFM probe preparation, based on electron beam methods, and discuss the possibilities
for batch fabrication of such advanced MFM tips. We show that the advanced probes allow high-resolution imaging of fine magnetic
structures within thin-film permalloy elements without perturbing them. Additionally, we present high-frequency MFM measurements
on a hard disk write head.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-681/302-3790, E-mail: m.koblischka@mx.uni-saarland.de 相似文献
16.
A. Dinia S. Zoll M. Gester D. Stoeffler J.P. Jay K. Ounadjela H.A.M. van den Berg H. Rakoto 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(2):203-214
The structural, magnetic and transport properties of Co/Rh sandwiches grown by ultra high vacuum evaporation and sputtering
have been studied. High-energy electron diffraction observations during the growth reveal that both Co and Rh layers have
been stabilised in the (111) fcc structure for the evaporated sandwiches. X-ray measurements performed on sputtered samples
show a predominant fcc polycrystalline structure of the stacks with a preferential (111) texture. Magnetisation and magnetoresistance
measurements show a very strong antiferromagnetic exchange coupling for thin Rh layers, reaching for 4.8? Rh, the strongest ever observed in exchange coupled systems. This value is in good agreement with the value of obtained by ab initio calculations for Co/Rh (hcp) superlattices. This is explained by the magnetic nature of the Co/Rh interfaces. Indeed, the
variation of the measured saturation magnetisation as a function of the Co layer thickness shows no evidence of Co moment
reduction for the Co atoms located at the interfaces, even for the very thin layers. The value of the preserved magnetic moments
of the cobalt atoms at the interfaces is confirmed by ab initio calculations for Co/Rh superlattices taking the intermixing into account.
Received: 18 February 1998 / Received in final form: 30 April 1998 /
Accepted: 29 May 1998 相似文献
17.
R. Steiner H.-G. Boyen M. Krieger A. Plettl P. Widmayer P. Ziemann F. Banhart R. Kilper P. Oelhafen 《Applied Physics A: Materials Science & Processing》2003,76(1):5-13
[Fe/B]n ≥2 multilayers were prepared by thermal evaporation, ion-beam sputtering and laser ablation. By applying in situ electron spectroscopies
(UPS, XPS) and monitoring the electrical resistance during layer growth, evidence could be provided for the occurrence of
interface reactions within the range of studied deposition temperatures (77 K ≤T ≤300 K). These reactions result in amorphous
FexB100-x phases, which are spatially restricted to a width of less than 3 nm at the original interface. The amorphicity of the reacted
interlayers was unequivocally proven by additional high-resolution electron microscopy (HRTEM) and their characteristically
changed magnetic properties. Due to the well-defined width of the interface reaction, homogeneous amorphous FexB100-x films can be obtained by reducing the individual Fe and B layer thicknesses to below the above reaction depth, while for
larger thicknesses layer sequences of the crystalline/amorphous/crystalline type will result.
Received: 30 January 2002 / Accepted: 31 January 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +49-731/502-2963, E-mail: hans-gerd.boyen@physik.uni-ulm.de 相似文献
18.
[Fe/Ni]N multilayered structure grows epitaxially on the single crystalline MgO substrate. Due to the different directions of magnetic easy axes of Fe and Ni and the strong strain, large anisotropy dispersion is assumed. According to the layer model, the magnetization of Fe and Ni layers cannot follow each easy axis because of exchange coupling, and then the anisotropies are averaged out. The reduction of the effective anisotropy enhances with the decrease of periodic thickness. Thus, the coercivity of [Fe/Ni]N multilayers reduces with decreasing periodic thickness. 相似文献
19.
In this work, the variation of the magnetic moments of the Ni/Pt multilayers are studied using the linearized augmented plane waves (LAPW) method in the framework of the density functional theory (DFT) implemented in the version of WIEN2K program. The systems have been modeled by seven layers slab separated in z direction by a vacuum region of four substrate layers. We present the results of the dependence of the magnetic properties with respect to the thickness variation of the different multilayers. The modeling of these systems finds an important empirical support. Experiment and theory show the same trends for the magnetic moments: hybridization effects between Ni and Pt are mostly localized at the interface. 相似文献
20.
Influence of velocity in nanoscale friction processes 总被引:3,自引:0,他引:3
R. Prioli A.M.F. Rivas F.L. Freire Jr. A.O. Caride 《Applied Physics A: Materials Science & Processing》2003,76(4):565-569
Force-microscopy images of boric acid crystals were obtained experimentally and simulated with the use of a two-dimensional
mechanical model. An analysis of the stick and slip movement of the microscope tip shows that the energy-dissipation mechanism
is strongly influenced by the non-linear dynamics of the sliding system. The contributions of stick and viscous forces on
the energy dissipation (or friction forces) are studied as a function of the relative scanning velocity. At low relative velocities,
the stick forces are shown to be responsible for the energy dissipation. This energy is velocity-dependent, due to the coupling
between the two degrees of freedom of the sliding system. As the scanning velocity increases the stick forces are damped;
the viscous force is then predominant in the energy-dissipation process.
Received: 30 October 2001 / Accepted: 17 May 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +55-21/2295-9397, E-mail: prioli@vdg.fis.puc-rio.br 相似文献