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  • 1
    Digitale Medien
    Digitale Medien
    Anglo-American Znnovation (1989)
    Oxford, UK : Blackwell Publishing Ltd
    R & D management 19 (1989), S. 0 
    Details
    ISSN: 1467-9310
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Wirtschaftswissenschaften
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1467-9310.1989.tb00657.x
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  • 2
    Digitale Medien
    Digitale Medien
    Small-angle x-ray scattering characterization of agarose sols and gels (1989)
    s.l. : American Chemical Society
    Macromolecules 22 (1989), S. 180-188 
    Details
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ma00191a035
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  • 3
    Digitale Medien
    Digitale Medien
    3-Dimethyallylindole: an Antibacterial and Antifungal Metabolite from Monodora tenuifolia (1986)
    s.l. : American Chemical Society
    Journal of natural products 49 (1986), S. 534-537 
    Details
    ISSN: 1520-6025
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/np50045a031
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  • 4
    Digitale Medien
    Digitale Medien
    The stress dependence of the ΔE effect in Terfenol-D (abstract) (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 5426-5426 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The stress dependence of the intrinsic change in Young's modulus with magnetic field (the ΔE effect, DE) has been measured to 120 MPa in Terfenol-D (Tb0.27Dy0.73Fe2−x, 0〈x〈0.1) with the field H as a parameter. The sample, prepared by rf rapid zoning,1 consists of slablike dendrites with the [112¯] growth direction determining the longitudinal (stress and field) axis of the sample. A [111] direction is normal to the longitudinal axis. The data (Fig. 1) show an extremely large (eightfold) depression in Young's modulus, comparable to that found in Fe-based amorphous materials. Earlier measurements on polycrystalline samples yielded DE=1.6. The value of DE observed here is attributed to the "jumping'' of the magnetization between two easy axes of magnetization. These directions are stress dependent, parallel to the magnetically easy 〈111〉 directions at low stress. One rotates to a direction 14.75° from the [111] direction at high stress. A calculation of the stiff (high-field) Young's modulus in the [112¯] direction using "infinite field'' single-crystal elastic constants yielded a value of 114 GPa. The lower value in Fig. 1 is consistent with this result since Δc44∼1/H. Calculation of the field dependence of the modulus caused by "jumping'' of the moment will be presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.342360
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  • 5
    Digitale Medien
    Digitale Medien
    Anisotropic magnetostriction in Tb0.27Dy0.73Fe1.95 (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3787-3789 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The magnetostriction of a single crystal of Tb0.27Dy0.73Fe1.95 grown by the Bridgman technique was measured over the temperature range of magnetic anisotropy compensation (300–330 K). Using a growth rate of 3 cm/h, twinned dendrites were suppressed. We looked for, but found no evidence of, modification of the cubic structure by the resulting cellular [112] growth. Magnetostriction measurements along all four 〈111〉 axis are nearly identical. However, the magnetostriction is highly anisotropic, with λ100/λ111=0.06±0.02 at 300 K. The effects of this large magnetostriction anistropy are discussed. Of particular importance is the magnetostriction along nonprincipal axes. Here we find that the magnetization direction for maximum strain is not collinear with the strain measurement direction. Measurements along the growth [112¯] direction revealed the maximum magnetostriction with the magnetization 14.75° from [112¯]. Expressions which relate the direction of magnetization for maximum strain to the measurement direction are derived for magnetization rotation in the (110) and (100) planes. The existence of noncollinear maximum magnetostriction axes leads to a region of 180° domain wall motion near H=0 in transducer rods of Tb0.27Dy0.73Fe1.95 under compressive prestress. This portion of the magnetization curve is not accompanied by magnetostriction. Magnetostriction curves in nonsaturating magnetic fields also provide a method to determine the magnetic anistropy. Anisotropy constants calculated in this way are compared to those determined earlier by torque and magnetization measurements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.338646
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  • 6
    Digitale Medien
    Digitale Medien
    Ultrasensitive, wide frequency range magnetoelastic strain gage (abstract) (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3803-3803 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A new technique for measuring strain with extremely high resolution was developed. This technique relies on the ultrasensitive (high coupling factor) amorphous ribbons prepared by magnetic field annealing.Here certain ribbons (e.g., Metglas 2605SC, 2605S-2) when annealed in a transverse field achieve magnetomechanical coupling factors k33≈0.95.1 In this technique the sensitive ribbon is bonded in place on an aluminum bending member with a highly viscous liquid (η≈107 cP at 298 K). This procedure allows the ribbon to remain in a stress-free environment following an initial relaxation period of approximately 10 min. In this state the ribbon is in a "blocked'' (constant strain) condition while at the same time being stress-free. Since the susceptibility of the ribbon is highly strain dependent, a measurement of the susceptibility is a direct measurement of the strain. We define a figure of merit (FM) as (∂χ/∂ε)/χ in analogy with (∂R/∂ε)/R for a conventional strain gage. Values of FM of about 2×105 were obtained. This is three orders of magnitude better than semiconductor strain gages. The main features of this technique are its large dynamic range, high sensitivity and strain resolution, very small temperature dependence, and broad frequency range. In a simple device, we measured strains as low as 3×10−10 and secured a dynamic range of 104. The potential dynamic range exceeds 105. Measurements of FM and dynamic range were made from 0.01 to 1 Hz. We expect no deterioration in operational characteristics far above 1 Hz. Calculations also indicate only a slight temperature dependence of the FM from 0 to 500 K.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.338653
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  • 7
    Digitale Medien
    Digitale Medien
    Magnetostriction "jumps'' in twinned Tb0.3Dy0.7Fe1.9 (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 3910-3912 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Large "jumps'' in the magnetostriction have been observed in twinned single crystals of Tb0.3Dy0.7Fe1.9 (Terfenol-D) for magnetic fields parallel to the crystalline [112¯] direction. The interpretation of these large magnetostriction discontinuities is based upon a model of twinned dendritic Terfenol-D in which the magnetization of one twin jumps between two [111] directions while the magnetization of the remaining twin undergoes a continuous rotation of the magnetization. The field dependence of the magnetization and magnetostriction of cubic single crystals with λ111(very-much-greater-than)λ100 was calculated using an expression which included the anisotropy constants K1 and K2 and compressive loads along [112¯]. With K1=−0.6 J/m3 and K2=−2.0 J/m3 (values appropriate for Terfenol-D near room temperature), magnetization "jumping'' is predicted. For the twinned crystal, the jump in the magnetostriction was calculated to be greater than 1000 ppm. Because of this large magnetostriction, it is possible to configure a device to perform a substantial amount of work by the application of only a triggering magnetic field centered about an optimum bias field.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.340602
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  • 8
    Digitale Medien
    Digitale Medien
    An ellipsometry study of a hydrogenated amorphous silicon based n-i structure (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 4566-4571 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Spectroscopic ellipsometry measurements have been used as a probe to provide information on the structure of a hydrogenated amorphous silicon based n-i two-layer system. The n-i structure is prepared under the same conditions as an a-Si:H p-i-n cell with a thin (∼150 A(ring)) n layer deposited in a glow discharge from a mixture of SiF4, SiH4, H2, and PH3 on top of intrinsic a-Si:H. An effective medium approximation and a linear regression analysis have been used to determine the bulk microstructure of the thick (0.3 μm) n layer on quartz as a mixture of volume fractions of a-Si (0.74±0.01), c-Si (0.09±0.02), and void (0.17±0.03). When applied to the thin n layer in the solar-cell configuration, however, the corresponding analysis shows evidence of a 100-A(ring) overlayer of very low density a-Si, not observed on the thicker n-type material, which dominates the dielectric properties of the thin layer. These results are suggestive of nucleation and growth surface microstructure on the 150-A(ring) n layer and lead to the conclusion that, in the fabrication of high-performance a-Si:H based devices using thin layers, such structure must be minimized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.335361
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  • 9
    Digitale Medien
    Digitale Medien
    Flux pinning and scaling laws for superconducting V3Ga (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 3160-3167 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The electric field versus current density (E-J) characteristics of a multifilamentary V3Ga wire are presented for temperatures in the range 2.5 K≤T≤Tc in magnetic fields up to 15 T. The critical current density (Jc) is determined throughout the superconducting phase for this composite. The volume pinning force (Fp=Jc×B) obeys the Fietz–Webb scaling law which is of the separable form Fp=αBnc2(T)f(b), where Bnc2(T) is a function only of temperature and f(b) is a function only of reduced field b [b=B/Bc2(T)]. In addition, two other scaling laws of this separable variable form which characterize the variation of critical current densities throughout the sample and the flux flow state are explicitly determined. It is demonstrated that similarly to NbTi and Nb3Sn, the mechanism describing dissipation above Jc must incorporate the intermittent motion of fluxons or flux bundles across the superconductor such that only a fraction (∼10−5) of the flux-line lattice is in motion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.344153
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  • 10
    Digitale Medien
    Digitale Medien
    Topography, domain structure, and magnetostriction measurements on Tb0.5Dy0.5Fe2 under stress (abstract) (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 3747-3747 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have characterized a textured cylindrical sample of Tb0.5Dy0.5Fe2 (54 mm×6 mm diam) by topography and metallography. The topography shows long ( 20 mm) slender grains with a [110] axis along the sample axis. The grain boundaries are less than 1°. Domain walls can be seen by both Berg–Barrett technique and optical observations. This composition has a large anisotropy, Ki=5×106 erg/cm3. We find that under stress the magnetization occurs by "jumping'' of the moment from a [111] axis perpendicular to the axis to the [111] direction closest to the axis of the sample. A large hysteresis accompanies this effect. In comparison with samples of other RFe2 (R=rare earth) compositions, the results of the high stress magnetization and magnetostriction experiments show two features: (1) the sample saturates with a much sharper "knee,'' and (2) a much higher energy conversion is obtained. We conjecture the difference between this sample and the other RFe2 compounds is its lack of Widmanstatten precipitate, i.e., a much higher sample perfection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.334958
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