8
CHAPTER III OBJECTIVE AND BENEFIT
3.1 Objective
The main objective of this proposal is to elucidate the hole-electron doping symmetry in the high-T
c
cuprates and to find the key phenomena for explaining the appearance of high-T
c
superconductivity. In order to progress this research, we proposed to growth high quality polycrystalline samples of electron-doped high-T
c
superconducting cuprates Eu
2-x
Ce
x
Cu
1-y
Zn
y
O
4
. With these samples, the effects of Zn on the Cu-spin dynamics are investigated to clarify whether or not the dynamical stripe
correlations of spins and charges are observed in electron-doped system as observed in the hole-doped system. The advantage point of this sample rather than other types of
electron-doped system is that the absence of rare earth moments such as Pr
3+
moments in Pr
1-x
LaCe
x
CuO
4
. Using these samples, we can directly observe the behavior of Cu-spins dynamic and the effects of impurity to them.
3.2 Benefit
The study of Cu-spin dynamics by ZF- SR in electron-doped of Eu
2-x
Ce
x
Cu
1-y
Zn
y
O
4
will be the first experiments in the world to clarify the Cu-spin dynamics of electron- doped cuprates. If the stabilization of the Cu-spin fluctuations by Zn is observed in the
proposed system, it would be a good sign that the stripe-pinning model can globally explain the high-T
c
superconductivity as in the case of hole-doped systems. On the other hand, in case that any stabilization cannot be confirmed, that would be a good indication
that the stripe-pinning model is restricted to describe the superconductivity in the hole- doped systems and that the high-T
c
superconductivity in the electron-doped systems is essentially different from that of hole-doped systems. In any case, this proposed study
will give us the important information of the mechanism of superconductivity based upon the dynamical stripe correlations in the high-T
c
superconducting cuprates.
9
CHAPTER IV RESEARCH METHODOLOGY
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