Magnetization and Curie Temperature of Ferromagnetic Ultrathin Films: The Influence of Magnetic Anisotropy and Dipolar Interactions (invited)

1991 ◽  
Vol 231 ◽  
Author(s):  
P. Bruno
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Curie Temperature ◽  
Magnetic Anisotropy ◽  
Long Range ◽  
Ultrathin Films ◽  
Experimental Results ◽  
Dipolar Interactions ◽  
Surface Gradient ◽  
Theoretical Investigations

AbstractTheoretical investigations of the magnetization and Curie temperature of ferromagnetic ultrathin films in the presence of magnetic anisotropy and long-range dipolar interactions are presented. The Curie temperature of fcc (001) cobalt ultrathin films is calculated and compared with experimental results on Co/Cu (001) films. The influence of an external magnetic field, and the surface gradient of the magnetization are also discussed.

INFLUENCE OF AN EXTERNAL MAGNETIC FIELD ON THE DYNAMICS OF A NEW-PHASE NUCLEUS IN THE VICINITY OF THE FIRST-ORDER PHASE TRANSITION IN MAGNETS WITH DEFECTS PRESENT

2012 ◽  
Vol 26 (28) ◽  
pp. 1250183 ◽  
Author(s):  
VLADIMIR NAZAROV ◽  
RISHAT SHAFEEV
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Spin Reorientation ◽  
Critical Fields ◽  
First Order ◽  
Phase Nucleus ◽  
First Order Phase Transition ◽  
New Phase

Theoretically, with the aid of a soliton model, the evolution of a new-phase nucleus near the first-order spin-reorientation phase transition in magnets has been investigated in an external magnetic field. The influence of an external field and one-dimensional defects of magnetic anisotropy on the dynamics of such nucleus has been demonstrated. The conditions for the localization of the new-phase nucleus in the region of the magnetic anisotropy defect and for its escape from the defect have been determined. The values of the critical fields which bring about the sample magnetization reversal have been identified and estimated.

scholarly journals High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

2009 ◽  
Vol 152-153 ◽  
pp. 373-376 ◽  
Author(s):  
Stanislav O. Volchkov ◽  
Andrey V. Svalov ◽  
G.V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Finite Elements ◽  
Magnetic Anisotropy ◽  
Constant Magnetic Field ◽  
High Frequency ◽  
Complex Impedance ◽  
Rf Sputtering ◽  
Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

scholarly journals On the crustal bias of repeat stations in Romania

2013 ◽  
Vol 55 (6) ◽  
Author(s):  
Venera Dobrica ◽  
Crisan Demetrescu ◽  
Razvan Greculeasa ◽  
Anca Isac
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Curie Temperature ◽  
Magnetic Induction ◽  
Electromagnetic Induction ◽  
Reference Station ◽  
Lateral Variation ◽  
Field Campaigns ◽  
Induction Model ◽  
Geomagnetic Measurements

<p>A magnetic induction model has been applied to recordings obtained in 2010 during the field campaigns for geomagnetic measurements at the 26 repeat stations of the Romanian secular variation network. The model is based on the observation that a variable external magnetic field induces a response of the Earth's interior not only by electromagnetic induction, but also by magnetic induction in the magnetic rocks above the Curie temperature. The model computes coefficients of a linear relationship between recorded values of a certain geomagnetic element (X, Y, Z, or F) at the repeat station and recorded X, Y, Z values at a reference station (in this case, SUA observatory). Coefficients depend on magnetic permeabilities of rocks beneath the station and stand as a proxy for the anomaly bias characterizing the site. Maps of the lateral variation of this type of information were obtained and discussed.</p>

scholarly journals Unravelling the Anisotropic Behavior of Nickel—Wires Prepared through External Magnetic Field Assisted Hydrazine Reduction Method

2021 ◽  
Vol 11 (18) ◽  
pp. 8627
Author(s):  
Min-Soo Kim ◽  
Min-Ji Shin ◽  
Akshay Kumar ◽  
Kavita Kumari ◽  
Seok-Hwan Huh ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Saturation Magnetization ◽  
Synthesis Method ◽  
Ferromagnetic Behavior ◽  
Geometrical Shape ◽  
Face Centered Cubic ◽  
Minimum Diameter ◽  
Hydrazine Reduction

Ni wires, prepared through a hydrazine reduction, were exposed to external magnetic fields of different geometrical shape and configuration during the synthesis denoted as Ni-Non-Magnetic, Ni-Double, Ni-Single, Ni-Ring. Their effect on the wire morphology, magnetization and magnetic anisotropy was then investigated via various characterization techniques viz. X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (HR-FESEM), and vibrating sample magnetometer (VSM). The polycrystalline single phase of the Ni-wires with face centered cubic symmetry was confirmed through the analysis of XRD patterns. Analysis of HR-FESEM images revealed that the Ni-particles were aligned in form of wire-like morphology. The Ni-single sample formed the wires with minimum diameter compared to the parent sample. The magnetization measurements performed at 300 K and 50 K demonstrated the ferromagnetic behavior of all the samples. The room temperature saturation magnetization (MS) and anisotropy constant (K) of the Ni-wires were reduced upon providing the external field during synthesis. However, the low temperature (50 K) magnetization behavior was rather opposing, indicating enhanced values of MS and K. Among all, Ni-ring sample showed maximum anisotropy with a value of 3.84 × 104 erg/cm3 at 50 K. The ambiguous nature of the anisotropic constant and saturation magnetization ascribed partly to the variation in diameters of Ni-wires and to the intermittent spin-spin exchange interactions of unaligned/partially aligned particles during the synthesis. Briefly, in the present study, it was established that the morphology and magnetic anisotropy of the Ni-wires could be tailored through the external magnetic field assisted synthesis method.

The mmW Band Tamm States in One-Dimensional Magnetophotonic Crystals

2009 ◽  
Vol 152-153 ◽  
pp. 394-396 ◽  
Author(s):  
Sergey I. Tarapov ◽  
M. Khodzitskiy ◽  
S.V. Chernovtsev ◽  
D. Belosorov ◽  
A.M. Merzlikin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Theoretical Prediction ◽  
Experimental Results ◽  
One Dimensional ◽  
Magnetophotonic Crystals ◽  
Good Agreement

The mmW band photonic Tamm states in 1D magnetophotonic crystals are studied. It is shown the possibility to manipulate the eigenfrequencies of such states by an external magnetic field. Our experimental results are in a good agreement with theoretical prediction.

The thermal capillary migration properties and controlling technique of ferrofluids

2017 ◽  
Vol 231 (11) ◽  
pp. 1441-1449 ◽  
Author(s):  
Qingwen Dai ◽  
Wei Huang ◽  
Jingqiu Wang ◽  
Xiaolei Wang
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Saturation Magnetization ◽  
Experimental Results ◽  
Migration Behavior ◽  
Thermal Gradients ◽  
Cold Regions ◽  
External Forces

The thermal capillary migration describes a phenomenon where the thermal gradients on the surface drive a liquid to flow from warm to cold regions in the absence of external forces. In industry, it is of great importance to prevent the migration since it would lead to lubricant starvation on the moving components. In this paper, ferrofluids are employed to control the migration. The influence of external magnetic field on the migration of ferrofluids is studied. The effects of volume and saturation magnetization of ferrofluids are also investigated. Experimental results demonstrate that the external magnetic field intensities have a significant obstruction effect on the migration behavior. An effective method using electromagnet to control the migration and re-concentrate the migrated lubricant is proposed.

Temperatur- und Konzentrationsabhängigkeit der 115In-Knightshift im flüssigen In-Mn-System

1990 ◽  
Vol 45 (7) ◽  
pp. 851-856
Author(s):  
I. Senel ◽  
D. Quitmann
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Moments ◽  
Metallic Alloys ◽  
Experimental Results

AbstractNMR measurements of the 115In-Knightshift and the linewidth in liquid In-Mn are reported. They were carried out in an external magnetic field of about 4.0 T at concentrations 0, 3, and 6 at.% Mn at temperatures from 400 K to 1300 K. According to our experimental results there are no localized magnetic moments in the liquid In-Mn-system. The experimental results are discussed in the framework of theories on metallic alloys.

Magnetic alignment in 2212 Bi-based superconducting system: Part I. Magnetic orientation of Bi2Sr2Ca1−x(RE)xCu2O8−y [(RE) = Gd, Dy, Ho, Er] powder dispersed in epoxy resin at room temperature

1996 ◽  
Vol 11 (5) ◽  
pp. 1082-1085 ◽  
Author(s):  
S. Stassen ◽  
R. Cloots ◽  
Ph. Vanderbemden ◽  
P. A. Godelaine ◽  
H. Bougrine ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Epoxy Resin ◽  
Room Temperature ◽  
Magnetic Alignment ◽  
Magnetic Orientation ◽  
System Part ◽  
The Rare Earth

The magnetic anisotropy of rare-earth substituted 2212 materials (Bi2Sr2Ca0.8RE0.2Cu2Ox with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is oriented under an external magnetic field (4 T) in a direction that depends on the nature of the rare-earth used in the substitution. Both directions of observation (parallel or perpendicular to the field) were investigated. Splitting of (00l) peaks is neatly observed and discussed.

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