权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study of Strongly Correlated Condensed-Matter Systems under Multiple Extreme Conditions

多种极端条件下强相关凝聚态系统研究

基本信息

批准号：
10044083
负责人：
KITAOKA Yoshio
金额：
$ 3.97万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

This research project was planed to investigate the novel electron phases in strongly correlated-electron systems, heavy-fermion, high-temperature cuprate and low dimensional organic materials under multiple extreme conditions. Obtained results are listed below.1. On the basis of Cu-NQR measurements, we have found that the ground state in a series of CeィイD2xィエD2CuィイD22ィエD2SiィイD22ィエD2 compounds evolves from magnetically ordered phase at x=0.975 to heavy-electron superconducting (SC) phase at x=1.025. The sample of x=0.99 does not exhibit any trace of magnetic phase transition down to 0.012 K, but is dominated by slow magnetic fluctuations with low frequencies comparable to the NQR frequency. For the samples of x=1.00 and 1.025 such a state is expelled by the onset of the SC state.2. From the NQR results under pressure (P) on near stoichiometric CeィイD20.99ィエD2CuィイD22ィエD2SiィイD22ィエD2 (TィイD2cィエD2=0.65 K), an exotic superconducting (SC) state due to an interplay with slowly-varying-magnetic- … More fluctuation-modes was found to be suppressed and replaced by a strong heavy-fermion SC phase at minute pressures exceeding P〜0.2 GPa. The TィイD21ィエD2 data in the high-P range 0.85-2.58 GPa are shown to be accountable by the "SCR theory". In P<0.2 GPa, an exotic interplay between magnetic and SC phase is implied.3. The magnetic-field dependencies of the pseudogap behavior in the underdoped YBaィイD22ィエD2CuィイD24ィエD2OィイD28ィエD2 (Y1248) was measured up to 23 T at the NHMF Laboratory (Tallahassee, Florida) and up to 28.5 T on the slightly overdoped TISrィイD22ィエD2CaCuィイD22ィエD2OィイD26.88ィエD2 with TィイD2cィエD2=68 K (TI1212). In the overdoped TI1212, we showed that the scalings found in the T and magnetic field dependencies of 1/TィイD21ィエD2 and Knight shift are consistent with the superconducting (SC) fluctuations. By contrast, even though 23.2 T reduces TィイD2cィエD2 by 26% in Y1248, no effect is seen on the normal-state pseudogap behavior. This was ascribed as due to the stronger coupling nature of the pairing than in TI1212.We have thus clarified the novel characteristics of anomalous magentism and unconventional superconductivity in the heavy-fermion and high-TィイD2cィエD2 cuprate oxides under multiple extreme conditions. The present research project enabled us to open new frontiers in the field. Less

本研究计划在多种极端条件下研究强相关电子系统、重费米子、高温铜和低维有机材料中的新型电子相。得到的结果如下：1。在Cu-NQR测量的基础上，我们发现一系列Ce γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。x=0.99的样品在0.012 K以下没有磁相变的痕迹，而是以与NQR频率相当的低频慢磁波动为主。对于x=1.00和1.025的样本，这种状态被SC状态的开始所驱逐。从NQR结果压力(P)附近的化学计量CeィイD20.99ィエD2CuィイD22摊位ィエD2SiィイD22摊位ィエD2 (TィイD2cィエD2 = 0.65 K),一个奇异的超导(SC)因slowly-varying-magnetic的相互作用 - ... 更多fluctuation-modes被发现抑制,取而代之的是一个强大的heavy-fermion SC阶段平均绩点0.2分钟压力超过P ~。TィイD21ィエD2中的数据只显示范围0.85 - -2.58的绩点负责的“可控硅理论”。在P<0.2 GPa时，磁相和SC相之间存在一种奇异的相互作用。赝能隙的磁场依赖性行为underdoped YBaィイD22摊位ィエD2CuィイD24ィエD2OィイD28ィエD2 (Y1248)测定了23 T NHMF实验室(塔拉哈西,佛罗里达州)和28.5 T略overdoped TISrィイD22摊位ィエD2CaCuィイD22摊位ィエD2OィイD26.88ィエD2和TィイD2cィエD2 = 68 K (TI1212)。在overdoped TI1212,我们表明,落下的石块在T和1 / T的磁场依赖性ィイD21ィエD2和骑士与超导转变是一致的(SC)的波动。相比之下，即使23.2 T在Y1248中降低了26%的T γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ，但对正常状态赝隙行为没有影响。这是由于配对的耦合性质比TI1212更强。因此，我们澄清了在多种极端条件下，重费米子和高钛钛钴氧化物的异常磁性和非常规超导性的新特征。目前的研究项目使我们在这个领域开辟了新的前沿。少