Stress-induced Magnetic Anisotropy Research Articles

Estimation of residual stresses in railway wheels by means of stress-induced magnetic anisotropy

A nondestructive inspection technique, based on stress-induced magnetic anisotropy, provides a means of quantifying the residual stress distribution in railway wheels. An automatic prototype device has been constructed; calibration measurements were carried out to examine the sensitivity of the technique to metallurgical effects in the wheel grades of interest. The device was used to obtain residual stress information on new and thermally damaged wheels representing a range of service conditions. The validity of the technique is examined using additional strain gauge measurements. A relationship is established between the output of the device and net circumferential stress within the wheel rim.

In Situ Susceptibility Measurement of the Low Temperature Martensitic Transformation

An ac susceptometer was constructed in order to carry out in situ measurements of the of stainless steel SUS316L specimens in tension tests under cryogenic temperatures. Changes in are associated with the formation of a ferromagnetic ?' phase due to a martensitic transformation induced by deformation at 4.2K. The observed became larger as the load was removed during tension testing. The stress-induced magnetic anisotropy seems to lower the of the specimen under tension. The true susceptibility derived from successive loading and unloading experiments is conjectured to reflect the proportion of martensite.

Magnetic analysis of the stress in nickel films obliquely deposited by sputtering

The stress in nickel films obliquely deposited by rf diode sputtering was investigated by analyzing the magnetic anisotropy. The incidence angle, defined as the angle between the substrate normal and the target normal, was 45° and the substrate temperature T s ranged from 333 to 493 K. The argon gas pressure during deposition was 16 Pa and the deposition rate was about 0.7 nm/s. In addition to the stress-induced magnetic anisotropy in the film plane we found a large stress-induced magnetic anistropy in the direction parallel to the column axis. The latter stress increases with decreasing T s and its magnitude is estimated as 3 × 10 8 N/m 2 at T s of 333 K.

Noncontact torque sensor using the difference of maximum induction of amorphous cores

A novel noncontact torque sensor which uses the difference of the maximum magnetic induction of two cores was constructed. The torque sensor utilizes the change in the maximum magnetic induction by AC magnetization due to the stress-induced magnetic anisotropy of negative magnetostrictive amorphous ribbons which are attached on a rotatable shaft in a chevron pattern. This sensor shows that the linearity was better than 1%, and the transient torque can be measured at the sampling rate of 10 kHz, which is the same as the magnetizing frequency of the core. >

極低温におけるマルテンサイト変態のその場帯磁率観察

An ac susceptometer was constructed in order to carry out in situ measurements of the of stainless steel SUS316L specimens in tension tests under cryogenic temperatures. Changes in are associated with the formation of a ferromagnetic ?' phase due to a martensitic transformation induced by deformation at 4.2K. The observed became larger as the load was removed during tension testing. The stress-induced magnetic anisotropy seems to lower the of the specimen under tension. The true susceptibility derived from successive loading and unloading experiments is conjectured to reflect the proportion of martensite.

Magnetic Anisotropy of Ni Films Prepared by Ion Beam Sputtering

The magnetic anisotropy in Ni films deposited by ion beam sputtering (IBS), triode rf sputtering and diode rf sputtering, was studied in relation to the internal stress in the films. A strong in-plane easy-axis magnetic anisotropy (K u ? -5 × 105 erg/cm3) was observed in IBS Ni films deposited at room temperature under an accelerating voltage exceeding 1 kV. The internal compressive stress was found to be as large as -1.2 × 1010 dyn/cm2, which caused a stress-induced magnetic anisotropy of about -1.2 × 106 erg/cm3 in the IBS Ni films. There is some positive contribution to the magnetic anisotropy, possibly due to the anisotropic internal shape effect (K int ? = 6 × 105 erg/cm3). Both this perpendicular magnetic anisotropy and the stress-induced in-plane anisotropy decreased with increasing substrate temperature during deposition. It is possible to obtain a stress-free, isotropic IBS Ni film at an appropriate substrate temperature (250 to 300°C) and at an appropriate ion beam accelerating voltage (1.1 kV).

Effect of stress annealing on the magnetostriction constant and induced magnetic anisotropy in [Co 1− xNi x] 75Si 15B 10 metallic glasses

Amorphous ribbons of composition [Co 1− x Ni x ] 75Si 15B 10 (0 < x < 0.30) were annealed by means of electrical current while applying a tensile stress. After thermal treatments, the magnetostriction constant and induced magnetic anisotropy were determined at room temperature. The strength of the induced anisotropy and the magnetostriction constant depends on the annealing temperature, the thermal history of the sample and the composition in two of these samples by conventional annealing under stress. Previous discussions on the kinetics of field- and stress-induced magnetic anisotropy are extended. The influence of stress annealing on the temperature dependence of the magnetostriction of the samples, in order to analyse λ s(T) in terms of one-ion and two-ions spin correlation functions, has been also investigated.

Stress-Induced Perpendicular Magnetic Anisotropy in PtMnSb Thin Films

Stress-induced perpendicular magnetic anisotropy is studied for PtMnSb thin films deposited on various substrates having different expansion coefficients. The magnetostriction constant λ of PtMnSb thin film is -30 × 10-6. The film's perpendicular magnetic anisotropy constant Ku increases as tensile thermal stress in the film plane increases.

イオンビームスパッタＮｉ薄膜の磁気異方性

The magnetic anisotropy in Ni films deposited by ion beam sputtering (IBS), triode rf sputtering and diode rf sputtering, was studied in relation to the internal stress in the films. Strong in-plane easy magnetic anisotropy (Ku∼-5 ×105 erg/cm3) was observed in IBS Ni films deposited at an acceleration voltage above 1 kV at room temperature. The internal compressive stress was found to be as large as -1.2×1010 dyn/cm2, which causes a stress-induced magnetic anisotropy of about -1.2×106 erg/cm3 in the IBS Ni films. There is some positive contribution to the magnetic anisotropy, possibly due to anisotropic internal shape effect (Kint∼6 ×105 erg/cm3). Both this perpendicular magnetic anisotropy and the stress-induced in-plane anisotropy are reduced with increasing substrate temperature during deposition. It is possible to obtain a stress-free isotropic IBS Ni film at an appropriate substrate temperature (250∼300°C) and an acceleration voltage (1.1 kV) of the ion beam

Magnetic anisotropy of IBS Ni films

The magnetic anisotropy in Ni films deposited on Pyrex glass substrates by different sputtering methods, i.e., ion beam sputtering (IBS), triode rf sputtering, and diode rf sputtering, was studied in relation to the internal stress in the films. Strong in-plane easy magnetic anisotropy (Ku=−4.9×105 erg/cm3) was observed in IBS Ni films. The average in-plane stress in the IBS film was estimated from the radius of convex curvature of the disk substrate as large as −1.2×1010 dyn/cm2 (a negative sign implies the compressive stress), which is due to the atomic peening effect by kinetic incident atoms during deposition. The stress-induced magnetic anisotropy is calculated to be about −1.2×106 erg/cm3, which is overwhelming to the observed magnetic anisotropy in the IBS Ni film. Positive Ku and tensile internal stress, one or two order of magnitude smaller in absolute values than that in IBS film, were observed in Ni films prepared by the other sputtering methods.

STUDY ON THE COERCIVITY OF RF SPUTTERED IRON OXIDE THIN FILMS

The study on magnetic properties of RF sputtered iron oxide thin films was carried out systematically. More specifically, the temperature dependence (77-500 K) of the coercivity and the variation of coercivity with different iron oxide phases such as the as-sputtered Fe3O4, partially transformed Fe3O4/(γ-Fe2O3), and γ-Fe2O3, were investigated. Comparing the theoretical analyses with the experimental results, the contributions to the coercivity from shape anisotropy, magnetocrystalline anisotropy, and stress-induced magnetic anisotropy were obtained separately. And the first-order crystalline anisotropy constant K1 vs. temperature for Fe3O4 and γ-Fe2O3 films was derived from Ms(T) and Hc(T) over the temperature range of 100-500 K.

Origins of stress-induced perpendicular magnetic anisotropy of sputtered iron oxide thin films

CoCr-doped γ-Fe 2 O 3 thin films prepared by RF sputtering and annealing processes exhibit stress-induced perpendicular magnetic anisotropy. This stress is found to be caused by both the ion bombardment on the film surface during sputter-deposition and the lattice misfit between the film and the substrate. The thermal effects play a less important role in causing stress in the films examined in this study.

Measurement of implantation profiles in garnet by transmission electron microscopy

Thin films of (SmYGdTm) <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Ga <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</inf> Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4.6</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf> have been produced by liquid phase epitaxy on {111} substrates of gadolinium-gallium garnet, masked with parallel stripes of photoresist, and implanted with ions of deuterium at 88 keV and doses ranging from 3.5 to 5.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> D+ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and/or with ions of oxygen at 100 keV and doses ranging from 0.95 to 8.6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> O+/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . These films are subsequently examined by transmission electron microscopy (TEM), incorporating a special cross-section technique, in order to reveal depth penetration (range) in unmasked regions and lateral diffuseness at mask edges for both D+ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and O+, thus providing a direct quantitative measure of implantation profiles. Shape and evolution of these profiles are determined as a function of implantation dose and compared with predicted stress-induced magnetic anisotropy within the implanted zone.

Stress-induced fracturing and magnetic susceptibility anisotropy in the Bleiburg-Kreuth mining region, Austria : Rathore, J S; Mauritsch, H J TectonophysicsV95, N1–2, 20 May 1983, P157–171

Stress-induced fracturing and magnetic susceptibility anisotropy in the Bleiburg-Kreuth mining region, Austria : Rathore, J S; Mauritsch, H J TectonophysicsV95, N1–2, 20 May 1983, P157–171

Stress-induced fracturing and magnetic susceptibility anisotropy in the Bleiberg-Kreuth mining region, Austria

A magnetic fabric study involving rock samples from above and below the ground was conducted in the mining region of Bleiberg-Kreuth, in Carinthia, Austria. Detailed magnetic fabric and fracture analyses show that the fractures and shear planes are related to the tectonically-produced magnetic fabric. Using this relationship, it is possible to delineate a time dependent tectonic evolution of the study region: the Bleiberg-Kreuth area underwent at least two phases of major compression with a period of relaxation in between. The shear angle, α, and the angle of internal friction, φ, in rocks are important parameters for predicting fracture failure. It is shown here how “in-situ” evaluation of these parameters can be made using the magnetic susceptibility anisotropy; a value of α = 33° and φ = 24° was obtained for the dolomitic rocks of the Bleiberg-Kreuth mines. Determination of the degree of deformation within different rock types and directions of movement along shear planes also are demonstrated.

Magnetic anisotropy in Co 73Mo 2Si 15B 10 and (Co 0.89Fe 0.11) 72Mo 3Si 15B 10 metallic glasses, induced by stress-annealing

Annealing temperature dependence of the stress-induced magnetic anisotropy in Co 73Mo 2Si 15B 10 (λ s < 0) and (Co 0.89Fe 0.11) 72Mo 3Si 15B 10 (λ > 0) metallic glass ribbons has been studied experimentally. The room temperature values of the induced anisotropy constants K depend strongly on the annealing conditions, and reveal a change of sign at annealing temperatures well below T cryst. It is concluded that transient creep and steady-state creep at the elevated temperature give rise to compressive and tensile stresses, respectively, in the expression for the magnetoelastic coupling energy at room temperature.

Ultrasonic velocities near the spin-reorientation transitions in ErFeO 3 at high pressure

The magnetic domain structure on (1 0 0), (1 1 0), (0 0 1) and arbitrary oriented planes of the R(FeCo)11Ti single crystals (R = Dy, Tb) is investigated. The role of the stress-induced magnetic anisotropy in the DS formation and the spin-reorientation transitions is analyzed. It is shown that the magnetoelastic contribution to the anisotropy in these compounds is large and can cause changes of the spin-reorientation temperatures and special domain patterns formation.

Temperature dependence of the growth-induced anisotropy of Ge-substituted garnet films by resonance techniques

Ferromagnetic resonance techniques have been used to measure the growth-and stress-induced uniaxial magnetic anisotropy of LPE grown garnet films of the nominal composition Y 1.64Eu 0.10Lu 0.30Ca 0.96Ge 0.96Fe 4.04O 12 from 130°K to near the Curie temperature, 455°K. The longitudinal and transverse resonance fields were measured prior and subsequent to an anneal at 1453°K. The growth-induced anisotropy, K G u ∼−0.03 × 10 4 ergs/cm 3 at 300°K, was found to be approximately 10% of the stress-induced anisotropy, and of opposite sign for these tensile films. The associated anisotropy field, 2 K G u M exhibited a reversal of slope, with a maximum occurring at 310°K. A model which assumes the existence of a surface anisotropy is proposed to explain these observations. The temperature dependence of the cubic anisotropy, the magnetization, the linewidth, and the exchange constant have been measured also.

A stress model for heteroepitaxial magnetic oxide films grown by chemical vapor deposition

A simple physical model is presented which predicts the sign and magnitude of stress in heteroepitaxial films. The model explains experimental observations of ferromagnetic resonance, domain structure, and crazing in magnetic oxide films grown by chemical vapor deposition (CVD) on non-magnetic substrates. It provides a means of predicting and developing compatible film-substrate combinations for epitaxial bubble domain materials utilizing a stress-induced uniaxial magnetic anisotropy. A basic result of the model, the conditions under which films can be grown in compression, has been verified experimentally for CVD iron garnets.

Stress-induced Magnetic Anisotropy of Rocks

ROCKS containing 1 or 2 per cent of magnetic minerals are so slightly ferromagnetic that reliable measurements of magnetostriction by the direct observation of changes in dimensions would, at best, be extremely difficult. However, an understanding of the magnetostriction of rocks is very desirable on account of the disagreement which has arisen concerning its possible role in palaeomagnetism1–4. The purpose of this communication is to report an experiment which shows that the saturation magnetostrictions of rocks are easily measured in terms of stress-induced anisotropy, and that, in the few rocks examined, they have values which would be expected from their known magnetic mineral contents.