Search results for "Remanence"
showing 10 items of 17 documents
Quantitative analysis of magnetization reversal in Ni thin films on unpoled and poled (0 1 1) [PbMg1/3Nb2/3O3]0.68–[PbTiO3]0.32piezoelectric substrat…
2016
The field angle dependence of the magnetization reversal in 20 nm thick polycrystalline Ni films grown on piezoelectric (0 1 1) [PbMg1/3Nb2/3O3](0.68)-[PbTiO3](0.32) (PMN-PT) substrates is analysed quantitatively to study the magnetic anisotropy induced in the film by poling the piezosubstrate. While the PMN-PT is in the unpoled state, the magnetization reversal is almost isotropic as expected from the polycrystalline nature of the film and corresponding to an orientation ratio (OR) of 1.2. The orientation ratio is obtained by fitting the angular dependence of normalized remanent magnetization to an adapted Stoner-Wohlfarth relation. Upon poling the piezosubstrate, a strong uniaxial anisotr…
Influence of magnetization on the applied magnetic field in various AMR regenerators
2017
International audience; The aim of this work is to assess the influence of a magnetic sample on the applied magnetic field inside the air gap of a magnetic circuit. Different magnetic sources including an electromagnet, a permanent magnet in a soft ferromagnetic toroidal yoke, as well as 2D and 3D Halbach cylinders are considered, using a numerical model. Gadolinium is chosen as magnetic material for the sample, due to its strong magnetocaloric properties and its wide use in magnetic refrigeration prototypes. We find that using uniform theoretical demagnetizing factors for cylinders or spheres results in a deviation of less than 2% in the calculation of internal magnetic fields at temperatu…
The effect of manufacturing tolerances on a tubular linear ferrite motor
2015
This study presents a numerical and experimental study on the effect of permanent magnet tolerances on the performances of a Tubular Linear Ferrite Motor. The statistical distribution of the magnetic characteristic of a set of commercial magnets is obtained experimentally while the performances of a the tubular motor are numerically evaluated. The performances that have been considered are: cogging force, end effect force and generated thrust. It has been shown that: 1)the statistical variability of the magnets modifies the time behavior of the cogging force; 2)the value of both the end effect cogging force and the generated thrust are directly linked to the values of then remanence field o…
Experimental validation of a distribution theory based analysis of the effect of manufacturing tolerances on permanent magnet synchronous machines
2017
An experimental study on the effect of permanent magnet tolerances on the performances of a Tubular Linear Ferrite Motor is presented in this paper. The performances that have been investigated are: cogging force, end effect cogging force and generated thrust. It is demonstrated that: 1) the statistical variability of the magnets introduces harmonics in the spectrum of the cogging force; 2) the value of the end effect cogging force is directly linked to the values of then remanence field of the external magnets placed on the slider; 3) the generated thrust and its statistical distribution depend on the remanence field of the magnets placed on the translator.
Electric field modification of magnetotransport in Ni thin films on (011) PMN-PT piezosubstrates
2015
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 062404 (2015) and may be found at https://doi.org/10.1063/1.4907775 This study reports the magnetotransport and magnetic properties of 20 nm-thick polycrystalline Ni films deposited by magnetron sputtering on unpoled piezoelectric (011) [PbMg1/3Nb2/3O3]0.68-[PbTiO3]0.32 (PMN-PT) substrates. The longitudinal magnetoresistance (MR) of the Ni films on (011) PMN-PT, measured at room temperature in the magnetic field range of −0.3 T < μ0H < 0.3 T, is found to depend on the crystallographic direction and polarization state …
Reorientation of magnetization states in Fe-nanostripe arrays on stepped W(110) caused by adsorption of CO, H2 and O2
1999
Abstract Fe-Nanostripe arrays of alternating double layer (DL) and monolayer (ML) stripes were grown on stepped W(1 1 0) surfaces by MBE. Magnetic properties were measured in situ in UHV using the polar and longitudinal magneto-optical Kerr effect (MOKE) during exposure to CO, H2 and O2. The longitudinal Kerr signal increases and the polar signal decreases with increasing exposure of all three gases. A sudden onset of perpendicular remanence was observed at exposures characteristic for each particular gas.
Hydrothermal Synthesis of Cobalt Ferrite Nanosized Powders
2015
Cobalt ferrite powders are synthesized by the co-precipitation technology, combined with the hydrothermal synthesis method and crystallite size, specific surface area (SSA), magnetic properties of synthesized products are obtained. All the synthesized ferrites are nanocrystalline single phase materials with crystallite size of 10-16 nm the SSA of 60±5 m2/g and the calculated particle size of 20±2 nm. Synthesized Co ferrites are characterized by the saturation magnetization MS of 59-60 emu/g, remanent magnetization Mr of 23 emu/g and coercivity Hc of 570-650 Oe.
Dielectric and magnetic properties of CdMoO4:Gd3+ single crystal
2014
Broadband dielectric spectroscopy and magnetic measurements provide experimental evidence that the CdMoO4:Gd 3+ single crystal is the paramagnet with low relative dielectric permittivity (er � 8), which slightly depends on the temperature and frequencies. Magnetization with zero coercivity and remanence is almost a universal function of l0H/T, characterizing superparamagnetic-like behavior. These results are being considered in a framework of the random distribution of the Ga 3+ ions in the tetragonal structure.
Relaxation of remnant magnetisation in YBa2Cu3O7−δ films
2007
Abstract The relaxation of the remnant magnetisation in optimally doped disk-shaped YBa2Cu3O7−δ films with the initially applied magnetic field H oriented along the c axis was measured using dc SQUID magnetometry. The temperature (T) dependence of the experimentally observed normalised magnetisation relaxation rate S exhibits three distinct regions. At high T, S(T) increases with increasing T, which can be explained in terms of plastic vortex creep. The well known plateau in the S(T) variation at intermediate T appears to be caused by collective (elastic) creep in a dynamically ordered vortex system. At low T, where S increases again with increasing T, the magnetisation relaxation is not in…
Temperature Dependence of Irradiation-Induced Magnetic Flux Loss in Nd 2 Fe 14 B Permanent Magnets
1990
Nd2Fe14B permanent magnets were irradiated with 20 MeV protons at 300 K and at 15 K, and the flux loss was measured as a function of the irradiation dose. The results show that at 15 K the Nd2Fe14B magnets can withstand particle radiation at least 1000 times more than at room temperature.