Fe tracer diffusion in L10 ordered FePt

2002 ◽  
Vol 753 ◽  
Author(s):  
Y. Nosé ◽  
T. Ikeda ◽  
H. Nakajima ◽  
K. Tanaka ◽  
H. Numakura
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Single Crystal ◽  
Diffusion Coefficients ◽  
Ion Beam ◽  
Tracer Diffusion ◽  
Ordered Structure ◽  
Tracer Diffusion Coefficient ◽  
Exponential Factor ◽  
Axis Direction

ABSTRACTTracer diffusion coefficient of 59Fe in FePt with the tetragonal L10 ordered structure has been measured by an ion-beam sputter-sectioning technique in the temperature range from 1173 to 1374 K. Anisotropy in diffusion has been studied using single-variant single-crystal specimens. The diffusion coefficient in the direction perpendicular to [001] axis (in the a-axis direction), Da, is larger than that in the [001] (c-axis) direction, Dc, as expected from the atomic arrangement of the L10 ordered structure. The ratio of the diffusion coefficients, Da/Dc, is 1.33.6 for Fe42Pt58 and smaller at higher temperatures. The activation energy for the diffusion is 259 ± 1 kJ/mol for Da and 309 ± 18 kJ/mol for Dc, while the pre-exponential factor is and , respectively in Fe42Pt58.

Temperature dependence of tracer diffusion coefficients in polystyrene

1986 ◽  
Vol 1 (1) ◽  
pp. 202-204 ◽  
Author(s):  
Peter F. Green ◽  
Edward J. Kramer
Keyword(s):  
Molecular Weight ◽  
Diffusion Coefficient ◽  
Shear Rate ◽  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
Tracer Diffusion Coefficient ◽  
Critical Molecular Weight ◽  
Tracer Diffusion Coefficients ◽  
Monomeric Friction Coefficient

The temperature dependence of the tracer diffusion coefficient D* of long deuterated polystyrene (d-PS) chains of molecular weight M>Mc, where Mc is the critical molecular weight for entanglement, diffusing into highly entangled PS matrices, each of molecular weight P = 2×107, is studied using forward recoil spectrometry. It is found that the temperature dependence of D*/T, reflected primarily in the monomeric friction coefficient, is accurately described by a Vogel equation. The constants that are used to fit these results are independent of M and are the same as those used to fit the temperature dependence of the zero shear rate viscosity of polystyrene.

Tracer diffusion coefficient of oxide ions in LaCoO3 single crystal

1984 ◽  
Vol 54 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Takamasa Ishigaki ◽  
Shigeru Yamauchi ◽  
Junichiro Mizusaki ◽  
Kazuo Fueki ◽  
Hifumi Tamura
Keyword(s):  
Diffusion Coefficient ◽  
Single Crystal ◽  
Tracer Diffusion ◽  
Tracer Diffusion Coefficient ◽  
Oxide Ions

Diffusion of 57Co in amorphous Fe–RE (RE = Dy, Tb, and Ce) and Fe–Si–B alloys

1993 ◽  
Vol 8 (9) ◽  
pp. 2231-2238 ◽  
Author(s):  
Kazumasa Yamada ◽  
Yoshiaki Iijima ◽  
Kazuaki Fukamichi
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Temperature Dependence ◽  
Tracer Diffusion ◽  
Atomic Size ◽  
Exponential Factor ◽  
Dc Sputtering ◽  
The Matrix ◽  
Diffusion Temperature ◽  
Order Of Magnitude

Tracer diffusion of 57Co in amorphous Fe100−xDyx (x = 20–40), Fe75Tb25, Fe67Ce33, and Fe80Si6B14 alloys prepared by dc sputtering has been studied at temperatures of 523 and 573 K. In the Fe–Dy alloys the diffusion coefficient of 57Co shows a maximum at 33 at.% Dy. The magnitude of the diffusion coefficient of 57Co in Fe75Tb25 is nearly equal to that in Fe75Dy25, while those in Fe67Ce33 and Fe80Si6B14 are about one order of magnitude less than the values in Fe67Dy33 and Fe80Dy20. This suggests that the atomic size of the diffusant and the density of the matrix are dominant in the diffusion. Temperature dependence of the diffusion coefficient D of 57Co in the amorphous Fe75Dy25 alloy has been determined in the range from 493–673 K. It shows a linear Arrhenius relationship expressed by D = 5.7 × 10−2 exp(−199 kJ mol−1/RT) m2 s−1. The magnitudes of the pre-exponential factor and the activation energy suggest that the cobalt tracer atoms in the amorphous Fe75Dy25 alloy diffuse by an interstitial-like mechanism.

scholarly journals Measurement of Tracer Diffusion Coefficient of Sulfur in Solid Calcium Sulfide by IMA

1979 ◽  
Vol 43 (12) ◽  
pp. 1181-1185 ◽  
Author(s):  
Takashi Otowa ◽  
Mutsuhiro Kobayashi ◽  
Kazuhiro S. Goto ◽  
Mayumi Someno
Keyword(s):  
Diffusion Coefficient ◽  
Tracer Diffusion ◽  
Calcium Sulfide ◽  
Tracer Diffusion Coefficient

Oxygen diffusion in amorphous and partially crystalline gallium oxide

2019 ◽  
Vol 21 (8) ◽  
pp. 4268-4275 ◽  
Author(s):  
Alexandra von der Heiden ◽  
Manuel Bornhöfft ◽  
Joachim Mayer ◽  
Manfred Martin
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficients ◽  
Low Temperatures ◽  
Oxygen Diffusion ◽  
Gallium Oxide ◽  
Tracer Diffusion ◽  
Tof Sims ◽  
Tracer Diffusion Coefficients ◽  
Oxygen Tracer

We established a TTT diagram of crystallisation of gallium oxide. Determination of oxygen tracer diffusion coefficients by IEDP/ToF-SIMS allowed us to access the activation energy for amorphous GaO1.5 at low temperatures.

scholarly journals Comparison of Polarographic Diffusion Current with that calculated using Tracer-Diffusion Coefficient

1972 ◽  
Vol 18 (5-6) ◽  
pp. 62-64
Author(s):  
Shigeo SAWADA ◽  
Kuniharu NISHIYAMA ◽  
Katsumi YOKOCHI ◽  
Makoto SUZUKI
Keyword(s):  
Diffusion Coefficient ◽  
Tracer Diffusion ◽  
Diffusion Current ◽  
Tracer Diffusion Coefficient

Oxygen Chemical Diffusion Coefficients of (U, Pu)O2-x

2017 ◽  
Vol 375 ◽  
pp. 84-90 ◽  
Author(s):  
Masashi Watanabe ◽  
Takeo Sunaoshi ◽  
Masato Kato
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Surface Reaction ◽  
Chemical Diffusion ◽  
Chemical Diffusion Coefficient ◽  
Thermo Gravimetry ◽  
Metal Ratio

The oxygen chemical diffusion coefficient in (U, Pu)O2-x was determined by thermo-gravimetry as functions of the Pu content, oxygen-to-metal ratio and temperature. The surface reaction was considered in the diffusion coefficient determination. The activation energy for the chemical diffusion coefficient was 60 kJ/mol and 65 kJ/mol, respectively, in (U0.8Pu0.2)O2-x and (U0.7Pu0.3)O2-x.

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