Synthesis and Orbital structure of structure- and valence-controlled layered manganites

结构和价态控制的层状锰酸盐的合成和轨道结构

• 批准号: 10440091
• 负责人: NAKAMURA Arao
• 金额: $ 9.73万
• 依托单位: Nagoya 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 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10440091/
• 关键词: perovskite manganites; photoinduced phase transition; double exchange system; ferromagnetic phase transition; ultrafasst laser spectroscopy; half-metal; 超高速レーザー分光; ペルプスカイト型酸化物; 電荷移動遷移; ヤーンテラーポーラロン; ペルブスカイト型酸化物; スモールポーラロン

We have systematically investigated electric, magnetic and optical properties of structure- and valencecontrolled manganites which show photoinduced magnetic transitions. The following is a major result.1. The temperature variations of the resistivity and specific heat have been measured for prototypical half-metallic ferromagnets R_<0.6>Sr_<0.4>MnO_3 by controlling the one-electron band width. We have observed the T^3 dependence of the resistivity which is interpreted in terms of the anomalous single-magnon scattering process in the half-metallic system.2. Photoinduced spin disorder and its dynamical behavior have been investigated for La_<0.7>Ca_<0.3>MnO_3. By optical injection of down-spin electrons into the Mn e_g orbital the spin disorder in the ferromagnetic phase is induced. We have found that the recovery time to the spin ordered state is lengthened from 30 ns at 5 K to 30 μs when the temperature approaches to the critical temperature of the phase transition. This result clearly demonstrates the critical slowing down of relaxation time in the phase transition.3. Photoinduced resistivity change in a La_<0.6>Ca_<0.4>MnO_3 film has been investigated with variation of the excitation photon energy and temperature. The magnitude of the photoinduced resistivity change steeply decreases with increasing temperature above the transition temperature of 315 K.Since the photoinduced signal is enhanced by injection of the down spin carriers, the resistivity change is ascribed to the photoinduced spin disorder in the ferromagnetic metallic state. This result indicates that one can detect photoinduced spin disorder with the resistivity signal.

我们已经系统地研究了结构CED磁性转变的电气，磁性和光学特性。用术语解释的电阻率。他在半金属系统中进行了异常的单磁散射过程。2。轨道诱导了铁磁相中的自旋障碍。在相位转换中。3。通过注入向下的自旋载体，电阻率的变化归因于铁磁金属中的光诱导的自旋疾病。

项目成果

K.Matsuba: "Photoinduced demagnetization and its dynamical behavior in a (Nd_<0.5>Sm_<0.5>)_<0.4>Sr_<0.4>MnO_3 thin film" Phys.Rev.B. 58. R4203-4206 (1998)

K.Matsuba：“(Nd_<0.5>Sm_<0.5>)_<0.4>Sr_<0.4>MnO_3 薄膜中的光致退磁及其动力学行为”Phys.Rev.B。

A.Machida 他: "Temperatue evolution of the 1.5-eV absorption band in doped manganites: Formation of John-Teller clusters" Phys.Rev.B. 58. 12540-12542 (1998)

A. Machida 等人：“掺杂锰氧化物中 1.5 eV 吸收带的温度演变：John-Teller 簇的形成” Phys.Rev.B. 58. 12540-12542 (1998)

X.Liu, et al.: "Photoinduced resistivity change due to spin-disorder in a manganite film"Jpn.J.Appl.Phys.. 39. L1233-L1235 (2000)

X.Liu等人：“由于亚锰酸盐薄膜中的自旋无序而引起的光致电阻率变化”Jpn.J.Appl.Phys.. 39. L1233-L1235 (2000)

K.Takenaka 他: "Optical reflectivity spectra measured on cleaved surfaces of La_<1-x>Sr_xMnO_3: Evidence against extremely small Drude weight"Journal of the Physical Society of Japan. 68(6). 1828-1831 (1999)

K.Takenaka等人：“在La_1-x>Sr_xMnO_3的劈裂表面上测量的光学反射率光谱：反对极小德鲁德重量的证据”日本物理学会杂志68(6)1828-1831(1999)。

Y.Moritomo 他: "Electronic phase diagram and phase separation in Cr-doped manganites"Physical Review B. 60(13). 9223 (9220)

Y. Moritomo 等人：“Cr 掺杂锰矿中的电子相图和相分离”物理评论 B. 9223 (9220)。