scholarly journals Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID) on cantilever tips

2017 ◽  
Vol 8 ◽  
pp. 2106-2115 ◽  
Author(s):  
Soraya Sangiao ◽  
César Magén ◽  
Darius Mofakhami ◽  
Grégoire de Loubens ◽  
José María De Teresa
Keyword(s):  
Magnetic Properties ◽  
Electron Beam ◽  
Saturation Magnetization ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Cobalt Content ◽  
Vortex State ◽  
Magnetic Vortex ◽  
Electron Holography ◽  
Electron Beam Induced Deposition

In this work, we present a detailed investigation of the magnetic properties of cobalt nanospheres grown on cantilever tips by focused electron beam induced deposition (FEBID). The cantilevers are extremely soft and the cobalt nanospheres are optimized for magnetic resonance force microscopy (MRFM) experiments, which implies that the cobalt nanospheres must be as small as possible while bearing high saturation magnetization. It was found that the cobalt content and the corresponding saturation magnetization of the nanospheres decrease for nanosphere diameters less than 300 nm. Electron holography measurements show the formation of a magnetic vortex state in remanence, which nicely agrees with magnetic hysteresis loops performed by local magnetometry showing negligible remanent magnetization. As investigated by local magnetometry, optimal behavior for high-resolution MRFM has been found for cobalt nanospheres with a diameter of ≈200 nm, which present atomic cobalt content of ≈83 atom % and saturation magnetization of 106 A/m, around 70% of the bulk value. These results represent the first comprehensive investigation of the magnetic properties of cobalt nanospheres grown by FEBID for application in MRFM.

scholarly journals Mechanical magnetometry of Cobalt nanospheres deposited by focused electron beam at the tip of ultra-soft cantilevers

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Hugo Lavenant ◽  
Vladimir Naletov ◽  
Olivier Klein ◽  
Grégoire de Loubens ◽  
Laura Casado ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Equilibrium Configuration ◽  
Vortex State ◽  
Magnetic Vortex ◽  
Hysteresis Curve ◽  
Focus Electron Beam ◽  
Sem Image ◽  
Magnetic Nanospheres ◽  
Electron Beam Induced Deposition

AbstractUsing focused-electron-beam-induced deposition, Cobalt magnetic nanospheres with diameter ranging between 100 nm and 300 nm are grown at the tip of ultra-soft cantilevers. By monitoring the mechanical resonance frequency of the cantilever as a function of the applied magnetic field, the hysteresis curve of these individual nanospheres are measured. This enables the evaluation of their saturation magnetization, found to be around 430 emu/cm3 independent of the size of the particle, and to infer that the magnetic vortex state is the equilibrium configuration of these nanospheres at remanence.SEM image of a 200 nm Co nanosphere grown at the tip of an ultra-soft cantilever by focus electron beam induced deposition.

scholarly journals Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

2018 ◽  
Vol 9 ◽  
pp. 1040-1049 ◽  
Author(s):  
Federico Venturi ◽  
Gian Carlo Gazzadi ◽  
Amir H Tavabi ◽  
Alberto Rota ◽  
Rafal E Dunin-Borkowski ◽  
...  
Keyword(s):  
Electron Beam ◽  
Domain Walls ◽  
Magnetic Moments ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Electron Holography ◽  
Magnetic Dipoles ◽  
Plane Field ◽  
Magnetic Domain Walls ◽  
Electron Beam Induced Deposition

The magnetic properties of nanowires (NWs) and square nanorings, which were deposited by focused electron beam induced deposition (FEBID) of a Co carbonyl precursor, are studied using off-axis electron holography (EH), Lorentz transmission electron microscopy (L-TEM) and magnetic force microscopy (MFM). EH shows that NWs deposited using beam energies of 5 and 15 keV have the characteristics of magnetic dipoles, with larger magnetic moments observed for NWs deposited at lower energy. L-TEM is used to image magnetic domain walls in NWs and nanorings and their motion as a function of applied magnetic field. The NWs are found to have almost square hysteresis loops, with coercivities of ca. 10 mT. The nanorings show two different magnetization states: for low values of the applied in-plane field (0.02 T) a horseshoe state is observed using L-TEM, while for higher values of the applied in-plane field (0.3 T) an onion state is observed at remanence using L-TEM and MFM. Our results confirm the suitability of FEBID for nanofabrication of magnetic structures and demonstrate the versatility of TEM techniques for the study and manipulation of magnetic domain walls in nanostructures.

MAGNETIC PROPERTIES OF MULTIFERROIC MATERIALS

2009 ◽  
Vol 23 (17) ◽  
pp. 3556-3560 ◽  
Author(s):  
X. W. QI ◽  
H. F. WANG ◽  
W. Q. HAN ◽  
P. H. WANG-YANG ◽  
J. ZHOU ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
Ferroelectric Phase ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Initial Permeability ◽  
Multiferroic Materials ◽  
Higher Temperature ◽  
Magnetic Hysteresis Loops

Magnetic properties of multiferroic materials consisting of ferroelectric phase and ferrite phase have been investigated. Typical magnetic hysteresis loops of prepared multiferroic materials have been observed. The coercivity increases with the increase of ferroelectric phase. However, the saturation magnetization of multiferroic materials linearly decreases with the increase of ferroelectric phase. On increasing the content of ferroelectric phase, the initial permeability of multiferroic materials decreases and the peak of the quality factor tends to shift toward higher frequency. The Curie temperature of prepared multiferroic materials shifts toward higher temperature with the increase of ferroelectric phase. The microstructures of prepared multiferroic materials also have been studied.

Tuning the Magnetic Vortex State in Magnetite Nanodiscs for Remote Control of Biological Signalling

2019 ◽  
Author(s):  
Danijela Gregurec ◽  
Alexander W. Senko ◽  
Andrey Chuvilin ◽  
Pooja Reddy ◽  
Ashwin Sankararaman ◽  
...  
Keyword(s):  
Remote Control ◽  
Ion Channels ◽  
Ground State ◽  
Magnetic Particles ◽  
Colloidal Stability ◽  
Vortex State ◽  
Magnetic Vortex ◽  
Electron Holography ◽  
Dipole Interactions ◽  
Magnetite Particles

In this work, we demonstrate the application of anisotropic magnetite nanodiscs (MNDs) as transducers of torque to mechanosensory cells under weak, slowly varying magnetic fields (MFs). These MNDs possess a ground state vortex configuration of magnetic spins which affords greater colloidal stability due to eliminated dipole-dipole interactions characteristic of isotropic magnetic particles of similar size. We first predict vortex magnetization using micromagnetic stimulations in sub-micron anisotropic magnetite particles and then use electron holography to experimentally investigate the magnetization of MNDs 98–226 nm in diameter. When MNDs are coupled to MFs, they transition between vortex and in-plane magnetization allowing for the exertion of the torque on the pN scale, which is sufficient to activate mechanosensitive ion channels in cell membranes.<br>

The Influence of Composition on Morphology, Structure and Magnetic Properties of Ni-Co Films on Aluminum Prepared by Electroplating Method

2013 ◽  
Vol 303-306 ◽  
pp. 2505-2509
Author(s):  
Yong Jun Hu ◽  
Dong Cao ◽  
Xi Qiang Li ◽  
Hui Ting Zheng ◽  
Xiao Ling Cheng ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Crystal Orientation ◽  
Nickel Content ◽  
Cobalt Content ◽  
Preferential Orientation ◽  
Content Increase ◽  
Composition Change ◽  
Alloy Films ◽  
Similar Composition

In this paper, Ni-Co alloy films with different composition were obtained by means of electroplating method. The morphology, structure and magnetic properties of Ni-Co alloy films with different Cobalt content are evaluated. The effect of the crystal orientation on the morphology of Ni-Co deposits with different compositon was discussed. The results showed that Ni–Co alloy films with Cobalt content decrease is composed of pyramidal, spindly, mixed pyramidal and spindly, and cellular particles respectively. To the deposits with similar composition, change of morphology is related to the preferential orientation. With the increase of the Nickel content, the saturation magnetization (Ms) value of the Ni–Co alloy films increases and then decreases sharply. The coercivety (Hc) value of the Ni–Co alloy films decreases with the Nickel content increase.

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

MAGNETIC PROPERTIES OF THE HIGH Tc SUPERCONDUCTORS BiSrCaCuO AND TlBaCaCuO

1989 ◽  
Vol 03 (01) ◽  
pp. 77-85 ◽  
Author(s):  
Y. D. DAI ◽  
C. LIN ◽  
W. B. ZHANG ◽  
S. Q. FENG ◽  
X. ZHU ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
High Tc Superconductors ◽  
Magnetic Current ◽  
High Tc ◽  
Bean Model ◽  
Current Densities ◽  
Magnetic Hysteresis Loops

Magnetic properties of the high T c superconductors BiSrCaCuO and TlBaCaCuO were investigated systematically. Magnetic current densities were calculated from magnetic hysteresis loops of bulk and powdered samples by Bean model. The results showed that flux pinning in these materials is much weaker than that in YBaCuO.

scholarly journals Ferroelectric and Magnetic Properties of Hot-Pressed BiFeO3-PVDF Composite Films

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Annapu V. Reddy ◽  
K. C. Sekhar ◽  
Navneet Dabra ◽  
A. Nautiyal ◽  
Jasbir S. Hundal ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coercive Field ◽  
Polyvinylidene Fluoride ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Composite Films ◽  
Hysteresis Loops ◽  
Liquid Phase Sintering ◽  
Magnetic Hysteresis Loops ◽  
Ferroelectric Hysteresis

The ferroelectric and magnetic properties of hot-pressed BiFeO3- (BFO) polyvinylidene fluoride (PVDF) composite films have been studied. The BiFeO3 (BFO) ceramics have been synthesized by a rapid liquid phase sintering technique. The X-ray diffraction (XRD) studies revealed that the impure phase observed in pure BFO ceramics was significantly reduced in the composite films. The presence of both ferroelectric and magnetic hysteresis loops confirms the multiferroic nature of the composite films at room temperature. A well-saturated ferroelectric hysteresis loop with a remanent polarization (Pr)∼4.8 μC-cm-2 and coercive field (Ec)∼1.55 kV/cm has been observed in composite thin films at room temperature. The magnetic hysteresis loops were traced at room temperature with SQUID. The remanent magnetization (Mr)∼3.0×10−3 emu/gm and coercive field (Hc)∼0.99 kOe was observed in the composite film. The magnetic polarization of the composite films has found to be enhanced as compared to pure BFO and correlated to reduction in BFO impure peak intensity.

Magnetic properties of a tri-decorated graphene structure: Monte Carlo study

2016 ◽  
Vol 30 (32) ◽  
pp. 1650233
Author(s):  
A. Jabar ◽  
N. Tahiri ◽  
L. Bahmad ◽  
A. Benyoussef
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Phase Diagrams ◽  
Ground State ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Monte Carlo Study ◽  
Magnetic Hysteresis Loops ◽  
Reduced Temperature ◽  
Good Agreement

In this paper, we study the magnetic properties of a tri-decorated [Formula: see text] graphene structure using Monte Carlo simulations (MCS). Indeed, we first elaborate the ground state phase diagrams and then, we found that from [Formula: see text] phases, the only stable configurations are: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. For low reduced temperature values, the partial magnetizations are found to be in good agreement with the corresponding ground state phase diagrams. The corresponding partial susceptibilities show a notable peak around the reduced temperature value 2.0 in the absence of the external magnetic field [Formula: see text] and crystal field [Formula: see text]. To complete this study, we present and discuss the magnetic hysteresis loops.

Sign in / Sign up

Export Citation Format

Share Document