Domain-growth kinetics in the geometrically frustrated isosceles triangular Ising spin system

几何受挫等腰三角形伊辛自旋系统中的畴生长动力学

基本信息

批准号：
14540364
负责人：
MITSUDA Setsuo
金额：
$ 2.3万
依托单位：
Tokyo University of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

We have studied(i)how the power law holds over wide tempetarwe range inAFphase, revealing that the gxnwth exponent n-02 is almost temperature independent and the pie-factor 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)domain-growth-kineucs in Ferri-magetic 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 domain-wall-motion by non-magnetic 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 domain-wail-motion by non-magnetic impurity can be explained by activation energy consideration ; theA/D-type 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 non-magnetic 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 domain-growth-kinetics 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 domain-growth-kinetics, an apparent incommensurate(IC)state, in which thermodynamically equivalent four types of AF domains, A, B, C, D, arrange quasi-regularly 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.

We have studied(i)how the power law holds over wide tempetarwe range inAFphase, revealing that the gxnwth exponent n-02 is almost temperature independent and the pie-factor 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)domain-growth-kineucs in Ferri-magetic phase在h_s = 1300 oe中，a'c'-type域壁被认为几乎自由移动，并且磁性敏感性c'显示幂律c'（t）= c'_ <eq>+at n〜02。（iii）（iii）在n〜02。对于X = 0.005的样品清楚地观察到了。由于已经解释了在带有X = 0.00的样品中广泛施加的磁场下域生长的各向异性抑制，因此可以通过激活能量考虑来解释这种各向异性固定固定效应对域 - 韦尔运动对域 - 韦尔运动的效果。 b diiction中的theA/d型结构域壁运动由conb2O6的等化等质链球菌tnangularlauice geomeby引起的自由磁链的随机逆转而主导，很容易影响非磁弹性的影响，而不是由替代材料的替代力造成的，因为iSiTition in dicrientation in diminity in dimitity in intoipation in inities inities inite Is is inite istition IsiTitie istition Is Isite IsiTe ISITE ISITIE ISITE ISITE ISITE ISITE ISITE ISITIE（II）（II）（II）（II）（II）（II）（II）。 domain-growth-kinetics 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 domain-growth-kinetics, an apparent incommensurate(IC)state, in which thermodynamically equivalent four types of AF domains, A, B, C, D, arrangement quasi-regularly along the b轴（Like/d/c/b/a/d ...）具有π/2的相移，取代了样品中看到的AF状态，x = 0.00作为低温状态，维持磁相边界的形状。