How to measure grain size

Size of crystallite from broadening of the Debye rings

Scherrer’s formula:

B: FWHM(full width at half maximum) on 2θ scale (radians)

or integral breadth(integrated intensity/maximum intensity)

t: diameter of the crystallites

ref. Elements of X-Ray Diffraction 3rd ed., B. D. Cullity and S. R. Stock, 388

Raoult’s Law and Henry’s Law

Roult’s Law ( Ω = 0 )

- the vapor pressure exerted by a component i in a solution is equal to the product of mole fraction of i in the solution and the saturated vapor pressure of pure liquid i at the temperature of the solution.

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Henry’s Law ( Ω < 0 )

- for dilute A-B solution(B>>A) and the Ω < 0, rate of evaporation r’_e(A) is independent of composition at small fraction of A

(r_e(A) is evaporation rate of pure, more precisely Ω = 0 )

At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid (Wikipedia)

ref. David R. Gaskell, “Chapter 9: The Behavior of Solutions”, in Introduction to the Thermodynamics of Materials 4th ed. Taylor & Francis, New York London, 2002, pp. 211-214

Gibbs-Duhem Eqn.

From known extensive thermodynamic properties of one component of a binary solution, those of the other component can be obtained!!

ref. David R. Gaskell, “Chapter 9: The Behavior of Solutions”, in Introduction to the Thermodynamics of Materials 4th ed. Taylor & Francis, New York London, 2002, pp. 216-218

Texture Coefficient

The Texture Coefficient proposed by Charles S. Barrett & T. B. Massalski is based on Harris’s work.

where,

I_{(h k l)}: measured relative intensity

I_{0(h k l):} relative intensity of the corresponding plane given in JCPDS data

n: number of reflections

the point is if a few reflections are available (i.e. number of n is small), the above Eqn becomes inaccurate.

ref.….. C. Barret and T.B. Massalski, Structure of Metals, Petgamon,

Oxford (1980), p. 1923

G. B. Harris, Phil. Mag., 43, 113 (1952)

the final..

FePtCu(5nm)/MgO sub

FePtCu(5nm)/MgO(3.2)/MgO sub w/o MgO annealing

    MgO with Power 50W 200W at 2mTorr

    MgO with Power 50W 200W at 15mTorr

FePtCu(5nm)/MgO(3.2)/MgO sub annealing the MgO at 600oC for 30 min

    MgO with Power 50W 200W at 2mTorr

    MgO with Power 50W 200W at 15mTorr

-> prependicular anistropy in FePtCu/MgO system is dominated by the surface state of MgO (only analysis via magnetic propties could be studied..)

[FePtCu/MgO]6/SiO2 – defective MgO
[FePtCu/MgO]6/SiO2 – cleaner MgO

MgO with Power 50W 200W at 2mTorr

MgO with Power 50W 200W at 15mTorr

-> for more microstructural, mangtical analysis..

1. Rate of MgO at 50W at 2 & 15mTorr
2. Rate of FePtCu at 2mTorr

A Super-Efficient Light Bulb

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후.. 가격, 안정성..머 문제가 있긴 있을긴데..