Budget Amount *help 
¥3,600,000 (Direct Cost : ¥3,600,000)
Fiscal Year 2003 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 2002 : ¥2,200,000 (Direct Cost : ¥2,200,000)

Research Abstract 
We have studied(i)how the power law holds over wide tempetarwe range inAFphase, revealing that the gxnwth exponent n02 is almost temperature independent and the piefactor Cis temperature dependent so that C(T)can be fitted to C_0exp(dE/k_BT)with a kind of activation energy dE/k_B〜10 K and(ii)domaingrowthkineucs in Ferrimagetic phase at H_s=1300 Oe where A'C'type domain wall is considered to move almost freely and the time evolution of magnetic suscepbblity c' shows power law c'(t)=c'_<eq>+At^n with n〜02.(iii)preserving anomalously low giowdi exponent n〜0.2, anisotropic pinning effect on domainwallmotion by nonmagnetic impunity was clearly observed for the sample with x=0.005. As anisotiopic suppression of domain growth under extemally applied magnetic field in the sample with x=0.00 has been explained, this anisotiopic pinning effect for domainwailmotion by nonmagnetic impurity can be explained by activation energy consideration ; theA/Dtype domain wall motion in the b diiection, which is dominated by the stochastic reversal of free magnetic chains due to the isosceles tnangularlauice geomeby of CoNb2O6, is easily disturbed by nonmagnetic impurity, while the domain wall motion in the a diiection is not because all sites have finite activation energy.(iiii)only 1% substitution is enough to suppress the domaingrowthkinetics in this system.(In the H_<//c>T magnetic phase diagram of the sample with x=0.01, as a consequence of suppression of the domaingrowthkinetics, an apparent incommensurate(IC)state, in which thermodynamically equivalent four types of AF domains, A, B, C, D, arrange quasiregularly along the b axis(likeA/D/C/B/A/D...)with phase shift of π/2, replaces AF state seen in the sample with x=0.00 as low temperature state, maintaining shape of the magnetic phase boundaries.
