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Studies of new low-dimensional quantum spin systems with the spin gap

具有自旋间隙的新型低维量子自旋系统的研究

基本信息

批准号：
16540334
负责人：
HASE Masashi
金额：
$ 1.98万
依托单位：
National Institute for Materials Science (NIMS)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

We have studied magnetism of Rb_2Cu_2Mo_3O_<12>. From the comparison between experimental and calculated results, we found that this cuprate can be considered as a model compound of a one-dimensional spin-1/2 Heisenberg system with ferromagnetic first-nearest-neighbor (1NN) and antiferromagnetic (AF) second-nearest-neighbor (2NN) competing interactions (competing system). Values of the 1NN and 2NN exchange interactions are estimated as J_1 = -138 K and J_2= 51 K (α = J_2/J_1 = -0.37). This value of a suggests that the ground state is a spin-singlet incommensurate state.We have also studied magnetism of Cu_2CdB_2O_6. There are two kinds of Cu sites [Cu(1) and Cu(2)], which are located adjacent to each other, and three kinds of exchange interactions (J_1,J_2, and J_3). AF dimers of the Cu(1) spins and AF uniform chains of the Cu(2) spins are formed by J_1 and J_3 interactions, respectively. The J_2 interaction connects the Cu(1) and Cu(2) spins. We found the appearance of antiferromagnet … More ic long-range order (AFLRO) with the transition temperature T_N= 9.8 K from the temperature dependence of the magnetic susceptibility and specific heat. We also found a 1/2 magnetization plateau in the magnetic fields above 23 T from the magnetic-field dependence of the magnetization. Experimental results agree with the quantum Monte Carlo results for the spin model with J_1 = 160 K, J_2= 38.8 K, and J_3= 9.7 K. Spin states can be understood as follows. In the magnetic fields below 23 T, the Cu(1) and Cu(2) spins form a nearly spin-singlet state and AFLRO, respectively. In the magnetic fields above 23 T, on the contrary, the nearly spin-singlet state of the Cu(1) spins are almost unchanged and the Cu(2) spins are almost polarized parallel to the magnetic field. As a result, we discovered that the nearly spin-singlet state and AFLRO coexist, although the interaction between the Cu(1) and Cu(2) spins cannot be ignored. Cu_2CdB_2O_6 is the first material in quantum spin systems that shows such coexistence in an atomic scale. Less

本文研究了Rb_2Cu_2Mo_3O_3的磁性<12>。通过对实验结果和计算结果的比较，我们发现这种铜氧化物可以看作是一个一维自旋为1/2的海森堡体系的模型化合物，该体系具有铁磁第一近邻（1 NN）和反铁磁（AF）第二近邻（2NN）竞争相互作用（竞争体系）. 1 NN和2NN交换相互作用的值分别为J_1 =-138K和J_2= 51 K（α = J_2/J_1 = -0.37）。我们还研究了Cu_2CdB_2O_6的磁性。Cu位有两种[Cu（1）和Cu（2）]，它们彼此相邻，有三种交换作用（J_1，J_2和J_3）。Cu（1）自旋的AF二聚体和Cu（2）自旋的AF均匀链分别由J_1和J_3相互作用形成。J_2相互作用连接Cu（1）和Cu（2）自旋。我们发现了反铁磁体的出现 ...更多信息从磁化率和比热随温度的变化关系，确定了该系列化合物的相变温度T_N= 9.8K，为1c长程有序（AFLRO）。我们还发现了一个1/2的磁化平台，在23 T以上的磁场从磁场依赖的磁化强度。对自旋模型（J1 = 160 K，J2 = 38.8K，J3 = 9.7K）的实验结果与量子MonteCarlo结果一致。自旋态可以理解如下。在低于23 T的磁场中，Cu（1）和Cu（2）自旋分别形成近自旋单重态和AFLRO。而在高于23 T的磁场中，Cu（1）自旋的近单重态几乎不变，Cu（2）自旋几乎平行于磁场极化。结果表明，虽然Cu（1）和Cu（2）自旋之间的相互作用不能忽略，但近自旋单重态和AFLRO态共存。Cu_2CdB_2O_6是量子自旋系统中第一个在原子尺度上表现出这种共存的材料。少

项目成果

期刊论文数量（37）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

1/3 magnetization plateau observed of in the spin-1/2 trimer chain compound Cu_3(P_2O_6OH)_2

自旋1/2三聚体链化合物Cu_3(P_2O_6OH)_2中观察到的1/3磁化平台

DOI：
发表时间：
2006
期刊：
Phys. Rev. B 73・10
影响因子：
0
作者：
S.Higashitani;M.Yamamoto;M.Miura;K.Nagai;Y.Nagato;H.Kuroe et al.;M.Hase et al.;M.Hase et al.
通讯作者：
M.Hase et al.

Magnetism of A_2Cu_2Mo_3O_<12> (A = Rb or Cs):Model compounds of a one-dimensional spin-1/2 Heisenberg system with ferromagnetic first-nearest-neighbor and antiferromagnetic second-nearest-neighbor interactions

A_2Cu_2Mo_3O_<12> 的磁性（A = Rb 或 Cs）：具有铁磁第一最近邻相互作用和反铁磁第二最近邻相互作用的一维自旋 1/2 海森堡系统的模型化合物

DOI：
发表时间：
2005
期刊：
J.Appl.Phys. 97-10
影响因子：
0
作者：
H.Kuroe;et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;H.Kuroe et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.
通讯作者：
M.Hase et al.

Effects of hydrostatic pressure on a one-dimensional ferromagnetic and anti ferromagnetic competing system Rb_2Cu_2Mo_3O_<12>

静水压力对一维铁磁和反铁磁竞争体系Rb_2Cu_2Mo_3O_<12>的影响

DOI：
发表时间：
2006
期刊：
AIP Conference Proceeding (in press)
影响因子：
0
作者：
H.Kuroe;et al.
通讯作者：
et al.

Effects of hydrostatic pressure on a one-dimensional ferromagnetic and anti ferromagnetic competing system Rb_2Cu_2Mo_3O_12

静水压力对一维铁磁和反铁磁竞争体系Rb_2Cu_2Mo_3O_12的影响

DOI：
发表时间：
2006
期刊：
AIP Conference Proceeding 印刷中
影响因子：
0
作者：
S.Higashitani;M.Yamamoto;M.Miura;K.Nagai;Y.Nagato;H.Kuroe et al.
通讯作者：
H.Kuroe et al.

Magnetism of A_2Cu_2Mo_3O_<12>(A=Rb or Cs): Model compounds of a one-dimensional spin-1/2 Heisenberg system

A_2Cu_2Mo_3O_<12>（A=Rb 或 Cs）的磁性：一维自旋 1/2 海森堡系统的模型化合物

DOI：
发表时间：
2005
期刊：
Journal of the Applied Physics 97(10)(In Press)
影响因子：
0
作者：
H.Kuroe;et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;H.Kuroe et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.;M.Hase et al.
通讯作者：
M.Hase et al.