Compositional Evolution And Magnetic Properties Of Nanocrystalline Fe 73.5cu1nb3si13.5b9

Melt-spun FeCuNbSiB ribbons were annealed at 540-550°C for various times (≤1 h). The development of a nanocrystalline structure was investigated by means of Mössbauer spectroscopy. From measured hyperfine fields and intensities the crystalline phase was inferred to be pure Fe 1-xSix, with x=0.18 after 1 h annealing. The residual amorphous volume fraction was determined to be ≅50%. With help of these results it has been possible to evaluate the amorphous contribution to magnetostriction in the nanocrystalline state. The development of a nanocrystalline structure was found to play a role in the main mechanisms of magnetic disaccommodation.711260086012Elfusa,Mineracao Jundu,Netzsc

Single Particle Scattering From Hot Electrons In Gaas

Two photon-absorption in GaAs from a pulsed Nd : Yag laser induced non-equilibrium distributions of electrons and optical phonons in the bulk of the material. The Nd : Yag laser radiation itself is used as a probe to search for population changes of optical phonons and carriers by means of Raman scattering. This allowed comparison of electron and phonon temperatures at different excitation levels. Electrons reached a temperature of 560° K for a lattice temperature of 300° K. © 1975.168969971Mooradian, Wright, (1966) Phys. Rev. Lett., 16, p. 999Wolff, (1968) Phys. Rev., 171, p. 436Wright, (1969) Light Scattering Spectra of Solids, p. 273. , also, Springer Verlag, New YorkMooradian, McWhorter, (1970) Proc. 10th Int. Conf. Phys. Semicond., p. 380. , S.P. Keller, J.C. Hensel, F. Stern, U.S.A. Atomic Energy CommissionShah, Leite, Scott, (1970) Solid State Commun., 8, p. 1089Shah, Leite, (1969) Phys. Rev. Lett., 22, p. 1304SHAH JAGDEEP (private communication)LLUESMA R.G., MENDES G., ARGUELLO C.A. and LEITE R.C.C., Solid State Commun. (to be published)FREITAS J.A. Jr., LLUESMA E.G., MATTOS J.C.V. and LEITE R.C.C., Solid State Commun. (to be published

Coercivity And Disaccommodation On Amorphous (fe1-xrx)80b20

Amorphous ribbons of the composition (Fe1-xRx)80B20 (R = Y, Ce, Pr, Nd, Sm, Gd, Ho, Er, Tm, Lu) (0{precedes above single-line equals sign}x{precedes above single-line equals sign}0.08) were studied by means of disaccommodation measurements, pinning field and coercivity measurements. The after-effect scales roughly with the square of the magnetostriction constant. The concentration dependence of the pinning field can be correlated with that of the coercivity. © 1994.1331-3270272Idzikowski, Wrzeciono, (1988) Phys. Stat. Solidi (a), 108, p. 375Khan, (1990) J. Magn. Magn. Mater., 86, p. L143Tejada, Martinez, Labarta, Grössinger, Hernando, (1990) J. Appl. Phys., 67, p. 5984Polak, (1992) Thesis, , University of ViennaJ.P. Sinnecker, M. Knobel, J.F. Saenger and R. Sato Turtelli, Proc. EMMA'93 (Kosice)Narita, Yamasaki, Fukunaga, (1980) IEEE Trans. Magn., 16, p. 435Grössinger, Wezulek, Sassik, The influence of the magnetostriction on the coercivity of amorphous ribbons (1990) Journal of Magnetism and Magnetic Materials, 83, p. 351Sinnecker, Grössinger, Turtelli, Exel, Greifeneder, Kuβ, (1994) J. Magn. Magn. Mater., 133, p. 20. , (this volume)Rezende, Turtelli, Missel, (1987) IEEE Trans. Magn., 23, p. 212

Initial Magnetic Permeability During The Development Of The Nanocrystalline State In Amorphous Ribbons

Low-field initial permeability (μi) has been measured at several steps of nanocrystallization in four amorphous Fe73.5Cu1Nb3Si13.5B9 ribbons produced by planar flow casting with different quenching rates (QRs) from the melt. It is observed that the increase in μi upon nanocrystallization is strongly influenced by the initial free-volume content of each sample. Samples produced with higher quenching rates exhibit a faster transformation kinetics and stronger enhancement of the initial permeability in the nanocrystalline state. Conventional heat treatments and accumulative annealings were performed on all the ribbons, in order to study the effect of their inhomogeneities and induced anisotropies. © 1994.1331-3255258Yoshizawa, Oguma, Yamauchi, (1988) J. Appl. Phys., 64, p. 6044Knobel, Turtelli, Rechenberg, (1992) J. Appl. Phys., 71, p. 6008Köster, Herold, Glassy Metals I: Ionic Structure (1981) Electronic Transport and Crystallization, p. 254. , H.J. Güntherodt, H. Becker, Springer-Verlag, BerlinKnobel, Sinnecker, Saenger, Turtelli, Effect of as-cast topological disorder on the magnetic properties of nanocrystalline Fe73.5Cu1Nb3Si13.5.B9 (1993) Philosophical Magazine Part B, 68, p. 861C. Polak, M. Knobel, R. Grössinger and R. Sato Turtelli, J. Magn. Magn. Mater. (to appear)P. Allia, M. Baricco, M. Knobel, P. Tiberto and F. Vinai, IEEE Trans. Magn. (in press)Knobel, Sinnecker, Turtelli, Rechenberg, Grössinger, (1993) J. Appl. Phys., 73, p. 6603Knobel, Santos, Torriani, Turtelli, (1993) Nanostr. Mater., 2, p. 399Luborsky, (1983) Amorphous Metallic Alloys, p. 360. , F.E. Luborsky, Butterworths, Londo

Low-temperature Behavior of the Magnetic-permeability Aftereffect In Amorphous Ferromagnetic-alloys

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Structural Evolution Of Nanocrystalline Fe73.5cu1nb3si13.5b9

In this work we report structural information obtained by a detailed X-ray diffraction (XRD) study of the crystallization kinetics of the nanocrystalline material obtained from the amorphous compound Fe73.5Cu1Nb3Si13.5B9. Instrumental effects were eliminated from the experimental XRD profiles using the Stokes deconvolution method. Subsequent fitting with Cauchy-Gauss functions led to a quantitative estimate of the constituent phases. Lattice constants and partial volume fractions were calculated from the fitting parameters. Average crystallite sizes and lattice strains were calculated from the crystalline intensity through the Warren-Averbach Fourier method. This structural analysis complements a recently published study of the compositional evolution and magnetic properties of the same ribbon using Mössbauer spectroscopy (MS) (1), and focuses attention on the discrepancies in the values of volume fractions of the structural components calculated from XRD and MS experimental data. © 1993.24399405Knobel, Turtelli, Rechenberg, (1992) J. Appl. Phys., 71 (12), p. 6008Gleiter, Nanocrystalline materials (1989) Progress in Materials Science, 33 (4)Yoshizawa, Oguma, Yamauchi, (1988) J. Appl. Phys., 64 (10), p. 6044Köster, Schünemann, Blank-Bewersdorff, Brauer, Sutton, Stephenson, Nanocrystalline materials by crystallization of metal-metalloid glasses (1991) Materials Science and Engineering: A, 133 A, p. 611Noh, Pi, Kim, Kang, (1991) J. Appl. Phys., 69 (8), p. 5921Müller, Mattem, Illgen, (1991) Z. Mettalkde, 82 Bd. (12 H.), p. 895Hampel, Pundt, Hesse, (1992) J. Phys.: Condens. Matter, 4, p. 3195Jiang, Aubertin, Gonser, Hilzinger, (1991) Z. Metallkde, 82 Bd. (9 H.), p. 698Allia, Beatrice, Vinai, Knobel, Turtelli, (1991) Appl. Phys. Lett., 59 (19), p. 2454Young, Wiles, Profile shape functions in Rietveld refinements (1982) Journal of Applied Crystallography, 15, p. 430Herzer, (1989) IEEE Trans. Magn., 25, p. 3327. , (1989)Pundt, Hampel, Hesse, (1992) Z. Phys. B - Condens. Matter, 87, p. 65Ch. Polak, M. Knobel, R. Grossinger and R.S. Turtelli, J. Magn. Magn. Mater. (in press)Mikkola, Cohen, (1966) Local Atomic Arrangements studied by X-ray Diffraction, p. 290. , J.B. Cohen, J.E. Hilliard, Gordon and Breach Publ, New Yor

The Development Of Nanocrystalline Fe73.5cu1nb3si13.5b9: Magnetism And Structural Disorder

In order to study the effect of the initial degree of topological disorder on the formation of the nanocrystalline state, two amorphous ribbons of composition Fe73.5Cu1Nb3Si13.5B9 produced in different laboratories were investigated. Measurements of hysteresis loops, disaccommodation and magnetostriction were performed on as-cast and nanocrystalline samples. An analytically solvable model describing the stress dependence of the coecivity is discussed. Two types of analysis of the approach to saturation are used to estimate the distribution function of the magnetization vectors. From the pinning field, the dimension of long-range order stresses in the nanocrystalline state is deduced. © 1994.1341112Yoshizawa, Oguma, Yamauchi, (1988) J. Appl. Phys., 64, p. 6044Herzer, (1992) J. Magn. Magn. Mater., 112, p. 258Gleiter, Nanocrystalline materials (1989) Progress in Materials Science, 33 (4)Herzer, (1989) IEEE Trans. Magn., 25, p. 3327Knobel, Sato Turtelli, Rechenberg, (1992) J. Appl. Phys., 71, p. 6008Schäfer, Hubert, Herzer, Domain observation on nanocrystalline material (1991) Journal of Applied Physics, 69, p. 5325Grössinger, Wazulek, Sassik, The influence of the magnetostriction on the coercivity of amorphous ribbons (1990) Journal of Magnetism and Magnetic Materials, 83, p. 351Kersten, (1943) Z. Phys., 44, p. 63Allia, Luborsky, Soardo, Sato Turtelli, Vinai, Magnetic relaxation in amorphous ribbons prepared with different quenching rates (1981) IEEE Transactions on Magnetics, 17, p. 2615Sato Turtelli, Vinai, (1990) Rev. Bras. Fis., 20, p. 203Narita, Yamasaki, Fukunaga, (1980) IEEE Trans. Magn., 16, p. 435Allia, Vinai, (1982) Phys. Rev. B, 26, p. 6141Allia, Vinai, (1986) Phys. Rev. B, 33, p. 422Allia, Vinai, (1981) IEEE Trans. Magn., 17, p. 1481Kronmüller, Theory of magnetic after-effects in ferromagnetic amorphous alloys (1983) Philosophical Magazine Part B, 48, p. 127Kronmüller, Moser, Rettenmeier, Micromagnetic analysis of magnetic after-effects in amorphous alloys by two-level systems (1984) IEEE Transactions on Magnetics, 20, p. 1388Kronmüller, (1981) Atomic Energy Rev. Suppl., 1, p. 255Vazquez, Fernengel, Kronmüller, (1989) Phys. Stat. Solidi (a), 115, p. 547J. Gonzales, M. Vazquez, E. T. de Lacheisserie and G. Herzer, unpublishedPolak, Grössinger, Holubar, Knobel, Sato Turtelli, Sassik, Determination of the Quenched-In State of Amorphous Ribbons Applying the Law of Approach to Saturation (1993) Key Engineering Materials, 81-83, p. 239Stoner, Wohlfarth, A Mechanism of Magnetic Hysteresis in Heterogeneous Alloys (1948) Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 240 A, p. 599Zhao-Hua, Dao-Sheng, (1981) J. Appl. Phys., 52, p. 1923Allia, Beatrice, Vinai, Knobel, Sato Turtelli, (1991) Appl. Phys. Lett., 59, p. 245