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μSR Study on the Dynamics of Charges and Spins in the High-T_c Oxides, and Development of High-Pressure μSR

高温氧化物中电荷和自旋动力学的μSR研究及高压μSR的发展

基本信息

批准号：
12640364
负责人：
WATANABE Isao
金额：
$ 2.3万
依托单位：
RIKEN (The Institute of Physical and Chemical Research)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

(1) μSR on the high-Tc oxidesIn order to investigate the dynamics of the stripe correlations of spins and holes, μSR measurements have been carried out on in the high-Tc oxides of La-, Bi2212- and-systems. It has been found from the non-magnetic impurity dependence on the La-system around the hole concentration of 1/8 per Cu that the dynamical stripes are statically stabilized by a small amount non-magnetic impurities (less than 1%) and destroyed by a large amount non magnetic impurities (more than 1%). From μSR measurements on the La-system around 100 K, the slowing down of the Cu-spin fluctuations that is expected to be caused by the stabilization of the dynamical stripes has been detected. Since the temperature where the stabilization of the Cu-spin fluctuations starts to be observed by the μSR measurement is consistent to the temperature where carriers tend to be localized, our result reveals that the suppression of the Cu-spin fluctuations couples with the localization of carriers.From μSR measurements on the Bi2212- and Y-systems, it has been found that the Cu-spin fluctuations are anomalously suppressed by a small amount non-magnetic impurities around the hole concentration of 1/8 per Cu. This result suggests the existence of the dynamical stripes in both systems.(2)High pressure μSRDesign and development works of a high-pressure cell for μSR measurements have been done. CuBe was chosen as the material of the cell. The maximum pressure was designed to be 1 Gpa. The cell was designed to be matched with the existing cryostat. The cell was manufactured and tested using the muon beam with a high momentum. We are planning to use the cell for real experiments after the pressure calibration at low temperatures.

(1)高tc氧化物上的μSR为了研究自旋和空穴的条纹相关动力学，在La-、Bi2212-和体系的高tc氧化物上进行了μSR测量。在1/8 / Cu的空穴浓度附近，非磁性杂质对la体系的依赖性表明，少量的非磁性杂质（小于1%）对动态条纹具有静态稳定作用，而大量的非磁性杂质（大于1%）则会破坏动态条纹。从100 K左右的μSR测量中，我们发现了cu自旋波动的减缓，这是由于动态条纹的稳定化引起的。由于μSR测量中cu自旋涨落开始稳定的温度与载流子倾向局域化的温度一致，我们的结果表明cu自旋涨落的抑制与载流子的局域化是耦合的。通过对Bi2212-和y -体系的μSR测量，发现在1/8 / Cu的空穴浓度附近有少量的非磁性杂质异常地抑制了Cu自旋涨落。这一结果表明在这两个系统中都存在动力条纹。(2)高压μSR：完成了测量μSR高压池的设计与研制工作。选择立方体作为单元的材料。最大压力设计为1gpa。该电池被设计成与现有的低温恒温器相匹配。该电池是用高动量的介子束制造和测试的。我们计划在低温下进行压力校准后，将电池用于实际实验。