Transport Measurements of Magnetic Multilayers at Reduced Lateral Dimensions

1997 ◽  
Vol 475 ◽  
Author(s):  
Y.D. Park ◽  
H.D. Hudspeth ◽  
T.J. Schultz ◽  
A. Cabbibo ◽  
J. A. Caballero ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contact Resistance ◽  
Applied Field ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Ion Milling ◽  
Multilayer Systems ◽  
Absolute Value ◽  
Lift Off ◽  
Nano Wires

Abstract We report on the fabrication and transport properties of magnetic multilayers with widths down to 100 nm. We employ e-beam processed nano-deposition masks to pattern magnetic multilayers which define nano-wires by lift-off or by a removal process such as ion-milling. Two different magnetic multilayer systems (antiferromagnetically coupled Co/Cu multilayers and NiFe/Cu/Co spin-valves) are investigated. Structures resulting from the lift-off process show high contact resistance and high resistivities while ion-milled structures show resistivities close to that of bulk. For Fe(50Å)/[Co(15Å)/Cu(20Å)]x20 /Cu(30Å), patterned nano-wire structures display no negative magnetoresistance but a positive magnetoresistance that is linear with applied field and no apparent hysteresis. For Ta(50Å)/NiFe(50Å)/Cu(35Å)/Co(20Å)/Cu(30Å), we found the resistance to decrease as the absolute value of magnetic field is decreased and found hysteresis to be present.

Contact resistance, coupling and hysteresis loss measurements of ITER Poloidal Field joint in parallel applied magnetic field

2021 ◽  
Author(s):  
Jianfeng Huang ◽  
Y. Ilyin ◽  
W.A.J. Wessel ◽  
Ruben Lubkemann ◽  
Erik Krooshoop ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contact Resistance ◽  
Applied Magnetic Field ◽  
Applied Field ◽  
Simulated Data ◽  
Hysteresis Loss ◽  
Ac Loss ◽  
Field Conditions ◽  
Ac Losses ◽  
First Time

Abstract The inter-strand contact resistance and AC losses were measured on an ITER PF Coil joint in a parallel applied AC magnetic field. In addition, the hysteresis loss was measured as a function of the angle with the applied magnetic field on a NbTi strand of the same type as in the joint with a Vibrating Sample Magnetometer (VSM). The AC loss measurements were performed at four applied field conditions for combinations of 0 or 1 T offset field and 0.2 or 0.4 T sinusoidal amplitude. The hysteresis loss of the joint was compared with the measured AC loss density of the NbTi strand for the same field conditions as the joint AC loss measurement but with varying the angle of the applied field. The subsequent cable twist angles affect the hysteresis loss since the critical current and penetration field depend on the angle of the applied field. It is found that 15.5° is an effective angle for the calculation of the hysteresis loss of joint when compared to the single strand measurement. The inter-strand contact resistance measurements cover all the typical strand combinations from the five cabling stages of the individual conductors, as well as the strand combinations across the two conductors to characterize the inter-strand including the copper sole resistivity. It’s the first time to measure the contact resistances and AC losses of the full-size ITER PF joint. By comparing the measured and simulated data in the JackPot-ACDC model, it’s also the first time to obtain the accurate inter-strand, inter-petal and strand to copper sole contact resistivities, which are the main input parameters for the further quantitative numerical analysis of the PF joints, in any current and magnetic field conditions.

Ion-Enhanced Dry Etching of Magnetic Multilayers: Post-Etch Cleaning and Effects of UV Illumination

1999 ◽  
Vol 585 ◽  
Author(s):  
H. Cho ◽  
K. P. Lee ◽  
K. B. Jung ◽  
F. Sharifi ◽  
J. Marburger ◽  
...  
Keyword(s):  
Sample Surface ◽  
Magnetic Multilayers ◽  
Magnetic Multilayer ◽  
Reaction Products ◽  
Ion Milling ◽  
Ion Density ◽  
Long Term Stability ◽  
Uv Illumination ◽  
Micron Size ◽  
Etch Rates

AbstractPatterning of magnetic multilayer structures of the type used for MRAMs (e.g. NiFeCo/CoFe/Cu/CoFe/NiFeCo) is generally performed with ion milling, but this can degrade the coercivity of small (micron-size) MRAM elements and lead to sidewall redeposition. In high ion density reactive plasmas (Cl2/Ar) it is possible to produce ion-enhanced desorption of otherwise involatile halogenated reaction products, and achieve practical etch rates (∼600 Å/min) for the multilayers. However, removal of the chlorinated etch products from the feature sidewalls is critically important to avoid corrosion. We have used de-ionized water rinsing or in-situ exposure to H2, O2 or SF6 plasmas for removal of these etch residues. Some slight degradation in magnetization was observed in O2 plasma treated structures, but the other cleaning procedures produced no change in magnetic properties and excellent long-term stability. UV illumination of the sample surface during etching is also found to enhance etch rates, as has been reported previously for room temperature etching of Cu.[1]

scholarly journals High-yield fabrication of perpendicularly magnetised synthetic antiferromagnetic nanodiscs

Nano Research ◽  
2021 ◽  
Author(s):  
Emma N. Welbourne ◽  
Tarun Vemulkar ◽  
Russell P. Cowburn
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Sacrificial Layer ◽  
Nanosphere Lithography ◽  
High Yield ◽  
Perpendicular Anisotropy ◽  
Ion Milling ◽  
Lift Off

AbstractSynthetic antiferromagnetic (SAF) particles with perpendicular anisotropy display a number of desirable characteristics for applications in biological and other fluid environments. We present an efficient and effective method for the patterning of ultrathin Ruderman-Kittel-Kasuya-Yoshida coupled, perpendicularly magnetised SAFs using a combination of nanosphere lithography and ion milling. A Ge sacrificial layer is utilised, which provides a clean and simple lift-off process, as well as maintaining the key magnetic properties that are beneficial to target applications. We demonstrate that the method is capable of producing a particularly high yield of well-defined, thin film based nanoparticles.

scholarly journals Deriving the skyrmion Hall angle from skyrmion lattice dynamics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
R. Brearton ◽  
L. A. Turnbull ◽  
J. A. T. Verezhak ◽  
G. Balakrishnan ◽  
P. D. Hatton ◽  
...  
Keyword(s):  
High Efficiency ◽  
Magnetic Field Gradient ◽  
Real Space ◽  
Magnetic Multilayer ◽  
Multilayer Systems ◽  
Space Technique ◽  
Hall Angle ◽  
Lattice State ◽  
The Many ◽  
Magnetic Skyrmions

AbstractMagnetic skyrmions are topologically non-trivial, swirling magnetization textures that form lattices in helimagnetic materials. These magnetic nanoparticles show promise as high efficiency next-generation information carriers, with dynamics that are governed by their topology. Among the many unusual properties of skyrmions is the tendency of their direction of motion to deviate from that of a driving force; the angle by which they diverge is a materials constant, known as the skyrmion Hall angle. In magnetic multilayer systems, where skyrmions often appear individually, not arranging themselves in a lattice, this deflection angle can be easily measured by tracing the real space motion of individual skyrmions. Here we describe a reciprocal space technique which can be used to determine the skyrmion Hall angle in the skyrmion lattice state, leveraging the properties of the skyrmion lattice under a shear drive. We demonstrate this procedure to yield a quantitative measurement of the skyrmion Hall angle in the room-temperature skyrmion system FeGe, shearing the skyrmion lattice with the magnetic field gradient generated by a single turn Oersted wire.

scholarly journals High-density Néel-type magnetic skyrmion phase stabilized at high temperature

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Hee Young Kwon ◽  
Kyung Mee Song ◽  
Juyoung Jeong ◽  
Ah-Yeon Lee ◽  
Seung-Young Park ◽  
...  
Keyword(s):  
High Temperature ◽  
High Density ◽  
Low Density ◽  
Memory Devices ◽  
Magnetic Multilayer ◽  
Multilayer Systems ◽  
Micromagnetic Simulations ◽  
Transmission Electron ◽  
Ultrahigh Density ◽  
Lorentz Transmission Electron Microscopy

AbstractThe discovery of a thermally stable, high-density magnetic skyrmion phase is a key prerequisite for realizing practical skyrmionic memory devices. In contrast to the typical low-density Néel-type skyrmions observed in technologically viable multilayer systems, with Lorentz transmission electron microscopy, we report the discovery of a high-density homochiral Néel-type skyrmion phase in magnetic multilayer structures that is stable at high temperatures up to 733 K (≈460 °C). Micromagnetic simulations reveal that a high-density skyrmion phase can be stabilized at high temperature by deliberately tuning the magnetic anisotropy, magnetic field, and temperature. The existence of the high-density skyrmion phase in a magnetic multilayer system raises the possibility of incorporating chiral Néel-type skyrmions in ultrahigh-density spin memory devices. Moreover, the existence of this phase at high temperature shows its thermal stability, demonstrating the potential for skyrmion devices operating in thermally challenging modern electronic chips.

scholarly journals Consideration of Magnetic Measurements for Characterisation of Ferrite–Martensite Commercial Dual-Phase (DP) Steel and Basis for Optimisation of the Operating Magnetic Field for Open Loop Deployable Sensors

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 490
Author(s):  
Mohsen Aghadavoudi Jolfaei ◽  
Lei Zhou ◽  
Claire Davis
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Initial Permeability ◽  
Open Loop ◽  
Dual Phase ◽  
Dp Steel ◽  
Ferrite Fraction ◽  
Lift Off ◽  
Steel Properties

The magnetic properties of commercial dual-phase (DP) steels (DP600, DP800 and DP1000 grades) were evaluated using initial permeability, incremental permeability and coercivity and correlated with the key microstructural differences between the grades. The ferrite grain sizes and ferrite fractions have been compared with the magnetic parameters obtained from minor and major magnetisation loops within each DP grade. It has been revealed that the incremental permeability increases with the applied magnetic field amplitude to reach a peak and then drops at a higher magnetic field, with the values being different for the three DP grades at a lower field and converging to a similar permeability value at the high field. The effects of ferrite grain size and phase fraction on the incremental permeability are considered, and it has been shown that the influence of ferrite grain boundaries on magnetic permeability is more dominant than the effect of ferrite fraction in commercial DP steel samples. An analysis of the correlation between coercivity and initial permeability with tensile strength shows that the initial permeability provides a slightly better prediction of strength for the steels examined, which is believed to be due to the fact that a combination of reversible and irreversible domain components affect the coercivity value, while the initial permeability is predominantly affected by reversible domain movements. Based on the trend between incremental permeability and applied magnetic field and the commercial EM sensor (EMspec) operating parameters, the effect of lift-off and hence magnetic field strength on the sensitivity to DP steel properties can be assessed.

A New Magnetooptical Effect Discovered on Magnetic Multilayers: The Magnetorefractive Effect

1995 ◽  
Vol 384 ◽  
Author(s):  
J. C. Jacquet ◽  
T. Valet
Keyword(s):  
Magnetic Field ◽  
Optical Transmission ◽  
Theoretical Calculations ◽  
Wavelength Region ◽  
Magnetic Multilayers ◽  
Light Wavelength ◽  
Metallic Multilayers ◽  
Magnetooptical Effect ◽  
Transmission Measurements ◽  
Magnetorefractive Effect

ABSTRACTWe show theoretically that the change in the magnetization structure of magnetic metallic multilayers under the application of a magnetic field shall be generally associated with a significant change of the refractive index. This constitutes a new magnetooptical effect: the magnetorefractive effect.Optical transmission measurements under an applied magnetic field through [Ni80Fe20/Cu/Co/Cu] multilayers, in the light wavelength region between 2 μm and 20 μm, clearly demonstrate the existence of the predicted effect and are found in reasonnable agreement with the theoretical calculations.

AB INITIO CALCULATIONS OF THE MAGNETO-OPTICAL RESPONSE OF LAYERED SYSTEMS

2002 ◽  
Vol 09 (02) ◽  
pp. 1135-1142
Author(s):  
HUBERT EBERT ◽  
ALEXANDER PERLOV ◽  
TILMANN HUHNE
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Optical Conductivity ◽  
Atomic Layer ◽  
Magnetic Multilayer ◽  
Layered Systems ◽  
Layer System ◽  
Multilayer Systems

The concept of the layer-resolved optical conductivity [Formula: see text] applied by means of a conventional band structure method is introduced. It is demonstrated that it allows a detailed discussion of the magneto-optical properties of magnetic multilayer systems. In particular it is found that the layer-projected optical conductivity [Formula: see text] of an atomic layer is influenced by only very few neighboring layers. This property can be exploited within the Baukasten principle, which aims to predict the magneto-optical properties of a complex layer system from the properties calculated for a closely related but simpler one.

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