Investigations on in situ Nanocrystallization and Magnetic Properties for Amorphous Fe78Si9B13 Ribbons

1999 ◽  
Vol 562 ◽  
Author(s):  
Xiangcheng Sun ◽  
A. Cabral-Prieto ◽  
M. Jose Yacaman ◽  
Wensheng Sun
Keyword(s):  
Amorphous Phase ◽  
Annealing Temperature ◽  
Amorphous State ◽  
Field Pattern ◽  
Transmission Electron ◽  
Optimum Annealing Temperature ◽  
Differential Scanning Calorimeters ◽  
Nanocrystalline Phases ◽  
Good Agreement

ABSTRACTThe amorphous state of ferromagnetic Fe78Si9B13 (Metglas 2605S-2) and itsnanocrystallization were investigated by in situ transmission electron microscope (TEM), Xraydiffraction (XRD), Mossbauer spectroscopy (MS), differential scanning calorimeters(DSC) and magnetic moment measurements. The Mössbauer spectrum exhibited anessentially symmetric hyperfine field pattern of 259KOe in as-quenched amorphous state atroom temperature. The Curie and crystallization temperature were determined to beTc=708K and Tx.= 803K, respectively. The Tx value was in good agreement with DSCmeasurement results. The occupied fraction of the nanocrystalline phases of α-Fe(Si) andFe2 at in situ optimum annealing temperature was about 57% and 43%, respectively. It isnotable that the magnetization of the amorphous phase decreases more rapidly withincreasing temperature than those of nanocrystalline ferromagnetism, suggesting thepresence of the distribution of exchange interaction in the amorphous phase or highmetalloid contents.

Investigations On In Situ Nanocrystallization And Magnetic Properties For Amorphous Fe78Si9B13 Ribbons

1999 ◽  
Vol 577 ◽  
Author(s):  
Xiangeheng Sun ◽  
A. Cabral-Prieto ◽  
M. Jose Yacaman ◽  
Wensheng Sun
Keyword(s):  
Amorphous Phase ◽  
Amorphous State ◽  
Field Pattern ◽  
Transmission Electron ◽  
Measurement Results ◽  
Optimum Annealing Temperature ◽  
Increasing Temperature ◽  
Differential Scanning Calorimeters ◽  
Nanocrystalline Phases

ABSTRACTThe amorphous state of ferromagnetic Fe78Si9B13 (Metglas 2605S-2) and its nanocrystallization were investigated by in situ transmission electron microscope (TEM), Xray diffraction (XRD), Mossbauer spectroscopy (MS), differential scanning calorimeters (DSC) and magnetic moment measurements. The Mössbauer spectrum exhibited an essentially symmetric hyperfine field pattern of 259KOe in as-quenched amorphous state at room temperature. The Curie and crystallization temperature were determined to be Tc=708K and Tx= 803K, respectively. The Tx value was in good agreement with DSC measurement results. The occupied fraction of the nanocrystalline phases of α-Fe(Si) and Fe2B at in situ optimum annealing temperature was about 57% and 43%, respectively. It is notable that the magnetization of the amorphous phase decreases more rapidly with increasing temperature than those of nanocrystalline ferromagnetism, suggesting the presence of the distribution of exchange interaction in the amorphous phase or high metalloid contents.

Lateral Reactions of Gaas with Ni Studied by Transmission Electron Microscopy

1985 ◽  
Vol 54 ◽  
Author(s):  
S. H. Chen ◽  
C. B. Carter ◽  
C. J. Palmstrøm ◽  
T. Ohashi
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Lateral Diffusion ◽  
Diffusion Couples ◽  
Product Phase ◽  
Transmission Electron ◽  
Good Agreement

ABSTRACTA new method has been developed for making self-supporting, thin films which can be used for the in situ study, by hot-stage, transmission electron microscopy, of the reaction between Ni and GaAs. The thin-film, lateral diffusion-couples have been used to study both the kinetics and the formation of new phases. The growth rate of the ternary compound, N2GaAs showed a parabolic time dependence. At an annealing temperature of 300*C, the present experimental results show that Ni is the diffusing species and that the Ga and As remain essentially immobile. Diffusion coefficients obtained by this method are in very good agreement with those which have been obtained using conventional thin-film techniques. The results of this new technique are particularly important in view of the difficulty in identifying the composition of the product phase by methods which do not have the same lateral resolution.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

In-Situ Study of Ti/TiN Stability under Nitrogen Anneal

1999 ◽  
Vol 564 ◽  
Author(s):  
P. W. DeHaven ◽  
K. P. Rodbell ◽  
L. Gignac
Keyword(s):  
Annealing Temperature ◽  
Time Range ◽  
Second Phase ◽  
Transformation Rate ◽  
Transformation Mechanism ◽  
Second Stage ◽  
Transmission Electron ◽  
Reaction Proceeds ◽  
Two Stages

AbstractThe effectiveness of a TiN capping layer to prevent the conversion of α-titantium to titanium nitride when annealed in a nitrogen ambient has been studied over the temperature range 300–700°C using in-situ high temperature diffraction and transmission electron microscopy. Over the time range of interest (four hours), no evidence of Ti reaction was observed at 300°C. At 450°C. nitrogen was found to diffuse into the Ti to form a Ti(N) solid solution. Above 500°C the titanium is transformed to a second phase: however this reaction follows two different kinetic paths, depending on the annealing temperature. Below 600°C. the reaction proceeds in two stages, with the first stage consisting of Ti(N) formation, and the second stage consisting of the conversion of the Ti(N) with a transformation mechanism characteristic of short range diffusion (grain edge nucleation). Above 600°C, a simple linear transformation rate is observed.

Ferromagnetic properties and Nanocrystallization behavior of Amorphous (Fe0.99Mo0.01)78Si9B13 Ribbons

2001 ◽  
Vol 674 ◽  
Author(s):  
Xiang-Cheng Sun ◽  
J. A. Toledo ◽  
S. Galindo ◽  
W. S. Sun
Keyword(s):  
Amorphous Phase ◽  
Magnetic Ordering ◽  
Metastable Phases ◽  
X Ray Diffraction ◽  
Ferromagnetic Properties ◽  
X Ray ◽  
Diffraction Patterns ◽  
Optimum Annealing Temperature ◽  
Increasing Temperature ◽  
Differential Scanning Calorimeters

ABSTRACTFerromagnetic properties and nanocrystallization process of soft ferromagnetic (Fe0.99Mo0.01)78Si9B13 ribbons are studied by transmission electron microscope (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS), differential scanning calorimeters (DSC) and magnetization measurements. The Curie and crystallization temperature are determined to be TC=665K and Tx = 750K, respectively. The Tx value is in well agreement with DSC measurement results. X-ray diffraction patterns had shown a good reconfirm of two metastable phases (Fe23B6, Fe3B) were formed under in-situ nanocrystallization process. Of which these metastable phases embedded in the amorphous matrix have a significant effect on magnetic ordering. The ultimate nanocrystalline phases of α-Fe (Mo, Si) and Fe2B at optimum annealing temperature had been observed respectively. It is notable that the magnetization of the amorphous phase decreases more rapidly with increasing temperature than those of nanocrystalline ferromagnetism, suggesting the presence of the distribution of exchange interaction in the amorphous phase or high metalloid contents.

A transmission electron microscopy investigation of inverse melting in Nb45Cr55

1997 ◽  
Vol 12 (7) ◽  
pp. 1872-1884 ◽  
Author(s):  
W. Sinkler ◽  
C. Michaelsen ◽  
R. Bormann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Phase ◽  
Amorphous State ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Medium Range ◽  
High Resolution Tem ◽  
And Calorimetry

In inverse melting, a supersaturated crystalline phase transforms polymorphously under heat treatment to the amorphous state. Inverse melting of body-centered cubic (bcc) Nb45Cr55 is studied using transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The crystalline to amorphous transformation is heterogeneous, initiating at the bcc grain boundaries. HRTEM reveals 2–3 nm domains with medium range order (MRO) in the amorphous phase. Preferred orientation of MRO domains is found on a scale corresponding to the precursor bcc grain size. Using HRTEM and calorimetry, MRO development in cosputtered Nb45Cr55 films is characterized and compared to that in the amorphous phase produced by inverse melting.

Formation and Crystallization of Amorphous Silicides at the Interface Between Thin Metal and Amorphous Silicon Films

1982 ◽  
Vol 18 ◽  
Author(s):  
S. R. Herd ◽  
K. Y. Ahn ◽  
K. N. Tu
Keyword(s):  
Amorphous Silicon ◽  
Amorphous Phase ◽  
Crystalline Silicon ◽  
Silicon Layer ◽  
Diffraction Peak ◽  
Gold Films ◽  
Cubic Form ◽  
No Formation ◽  
Transmission Electron

We investigated the interaction of extremely thin (less than 10 nm) crystalline gold and rhodium films with amorphous silicon by transmission electron microscope in situ annealing. In thin Au/Si bilayers an amorphous phase with a diffraction peak at d ≂ 0.226 nm is formed by thermal annealing between 150 and 200 °C. Depending on the thickness and composition, silicon sputtered onto thin gold films leads to the formation of a layer of amorphous silicon and a partially amorphous Au-Si layer during deposition. The silicon layer crystallizes by itself at temperatures as low as 150 °C, and at 300 °C the amorphous Au–Si layer crystallizes into a metastable gold silicide (for silicon-rich compositions). In Rh/Si bilayers an amorphous Rh–Si phase is formed by annealing to 300 °C and can be detected by electron diffraction for a rhodium thickness of less than 5 nm and compositions with more than 50% Si if completely reacted. Above 300 °C the amorphous Rh-Si crystallizes preferentially in the cubic form of RhSi for intermediate silicon compositions and in the orthorhombic form of RhSi for high silicon compositions. Excess amorphous silicon is not found to have a lowered crystallization temperature when in contact with the amorphous Rh-Si alloy, and crystalline silicon is only observed above 730 °C together with the cubic and/or orthorhombic RhSi. In Rh/Si bilayers with a thicker rhodium layer, no formation of an amorphous phase was observed on annealing; instead crystalline Rh2Si forms during annealing above 300 °C.

Phase Formation, Stability and Superconducting Properties of Mechanically Alloyed Yttrium-Nickel-Borocarbides

1998 ◽  
Vol 547 ◽  
Author(s):  
L. Ledig ◽  
D. Hough ◽  
C.-G. Oertel ◽  
J. Eckert ◽  
W. Skrotzki
Keyword(s):  
Amorphous Phase ◽  
Amorphous State ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Milling Parameters ◽  
Transmission Electron ◽  
Nanocrystalline And Amorphous ◽  
Nickel Borocarbides

AbstractThe solid state reaction of YNi2B2C by mechanical alloying of elemental powders has been investigated by X-ray diffraction, transmission electron microscopy and susceptibility measurements. Depending on the ball milling parameters either nanocrystalline YNi2B2C or an amorphous phase can be produced. Crystallization of the amorphous phase by annealing at 893 K produces YNi2B2C as major and Ni2B as minor intermetallic compound. Superconductivity is only observed in the annealed state. However, the transition temperature is much lower than in arc-melted samples. This is discussed with respect to the nanocrystalline and amorphous state as well as deviations from stoichiometry produced by impurities introduced during milling.

Defect Trapping and Precipitation Processes During Annealing of Cu and Au Implanted Si

1994 ◽  
Vol 354 ◽  
Author(s):  
J. Wong-Leung ◽  
E. Nygren ◽  
J. S. Williams ◽  
D. J. Eaglesham
Keyword(s):  
Annealing Temperature ◽  
Primary Concern ◽  
Temperature And Precipitation ◽  
System A ◽  
Transmission Electron ◽  
Device Processing ◽  
Long Time ◽  
Second Phases ◽  
Metallic Impurities

AbstractThe behaviour of metallic impurities in Si is an issue of primary concern in advanced device processing. This paper addresses the annealing behaviour of Cu and Au in Si when nanocavities are present within the substrate as potential gettering and precipitation sites. In-situ, ‘hot’ Rutherford backscattering has been used to study metal accumulation to cavities at the annealing temperature. Transmission electron microscopy has been used to study the final microstructure of the Au-Si and Cu-Si system. A range of interesting phenomena have been observed, including very efficient transient gettering of both Cu and Au to cavities at the annealing temperature and precipitation of second phases at cavities. Dissolution of accumulated metal from defect bands into solution occurs for long-time annealing. This behaviour is discussed in terms of supersaturated solid solubility processes, diffusion, defect-trapping and precipitation of Cu and Au in Si.

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