Lattice dynamics contribution to the magnetic properties of molecular magnets: Raman and ultrasonic studies

晶格动力学对分子磁体磁性的贡献：拉曼和超声研究

• 批准号: 25494349
• 负责人: Professor Dr. Peter Lemmens
• 金额: --
• 依托单位: Institut für Physik der Kondensierten Materie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/25494349?language=en
• 关键词: Lattice; dynamics; contribution; magnetic; properties

This proposal concerns high resolution Raman scattering and ultrasonic studies of two classes of molecular magnetic compounds: I) spin-crossover systems, which demonstrate spin state change under influence temperature and/or pressure as well light irradiation; II) single-molecular magnets consisting of polynuclear transition metal ion complexes bound by organic ligands. The main goal of this project is the investigation of the role of intermolecular vibrations for the cooperative behavior of spin crossover transitions for case I systems. Spin phonon interactions and the determination of phonon modes which strongly affect the efficiency of magnetic exchange paths will be main aim for case II systems. Raman scattering and ultrasonic studies will be performed in wide temperature range (2 K - 300 K), magnetic fields up to 7 T and under hydrostatic pressure up to 2GPa. The role and influence of lattice degrees of freedom on the spin state crossover mechanisms in the case I and in quantum tunneling mechanism of magnetization in the case II will be elucidated. The second goal of the project is the search of the spin state gap as well as its temperature evolution for case I systems and the manifestation of inelastic many spin effects in Raman spectra in case II systems. Lattice dynamical calculations will be executed through access to codes: WIEN2k, Gamess and others. The stability of different spin states against different type of lattice distortions will be analyzed with help of modified crystal approach with inclusion of spin-orbital interaction. The crystals to be investigated are tetranuclear and hexanuclear Fe, Mn12 and spin crossover systems available due to collaborations within the DFG Priority Programme 1137

本研究主要涉及两类分子磁性化合物的高分辨拉曼散射和超声波研究：I）自旋交叉系统，它在温度和/或压力以及光照的影响下表现出自旋状态的变化; II）由有机配体结合的多核过渡金属离子络合物组成的单分子磁体。本计画的主要目的是研究第一种情形下，分子间振动对于自旋交叉跃迁合作行为的作用。自旋声子相互作用和声子模式的确定，强烈影响的磁交换路径的效率将是主要的目标情况II系统。将在宽温度范围（2 K - 300 K）、高达7 T的磁场和高达2 GPa的静水压力下进行拉曼散射和超声研究。将阐明晶格自由度对情形I中的自旋态交叉机制和情形II中的磁化量子隧穿机制的作用和影响。该项目的第二个目标是寻找自旋态间隙以及它的温度演化的情况下，I系统和非弹性的许多自旋效应的表现在拉曼光谱的情况下II系统。晶格动力学计算将通过访问代码执行：WIEN 2k，Gamess等。不同自旋状态对不同类型的晶格畸变的稳定性将分析与包括自旋轨道相互作用的改进的晶体方法的帮助。由于DFG优先计划1137内的合作，将被研究的晶体是四核和六核Fe、Mn 12和自旋交叉系统

项目成果

A molecular magnet confined in the nanocage of a globular protein.

限制在球状蛋白纳米笼中的分子磁体

• DOI: 10.1002/cphc.200900708
• 发表时间: 2010
• 期刊: Chemphyschem : a European journal of chemical physics and physical chemistry
• 作者: Samir Kumar Pal;Rajib Kumar Mitra;Pramod Kumar Verma;Dirk Wulferding;Dirk Menzel;Thom Mitra;Peter Lemmens;Achim Müller
• 通讯作者: Achim Müller

Anomalous frequency and intensity scaling of collective and local modes in a coupled-spin tetrahedral system Cu2Te2O5Cl2

耦合自旋四面体系统 Cu2Te2O5Cl2 中集体和局部模式的反常频率和强度缩放

• DOI: 10.1103/physrevb.79.024416
• 发表时间: 2009
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: K. Y. Choi;H. Nojiri;N. S. Dalal;H. Berger;W. Brenig;P. Lemmens
• 通讯作者: P. Lemmens

Manipulation of Spontaneous Emission Dynamics of Organic Dyes in the Porous Silicon Matrix

多孔硅基体中有机染料自发发射动力学的调控

• DOI: 10.1007/s10895-009-0552-1
• 发表时间: 2010
• 期刊: Journal of Fluorescence
• 影响因子: 2.7
• 作者: A. Makhal;S. S. Sinha;P. Kumar;P. Lemmens;S. K. Pal
• 通讯作者: S. K. Pal

Spin state transformations of a 3d ion in the pyramidal environment and under lattice distortions

金字塔环境和晶格畸变下 3d 离子的自旋态变换

• DOI: 10.1088/0953-8984/19/15/156216
• 发表时间: 2007
• 期刊: Journal of Physics: Condensed Matter
• 作者: E. S. Zhitlukhina;K. V. Lamonova;S. M. Orel;P. Lemmens;Yu. G. Pashkevich
• 通讯作者: Yu. G. Pashkevich

Anomalous low-temperature behavior of the Co dimers in the oxo-halide CoSb2O3Br2

含氧卤化物 CoSb2O3Br2 中钴二聚体的异常低温行为

• DOI: 10.1016/j.jssc.2008.07.005
• 发表时间: 2008
• 期刊: Journal of Solid State Chemistry
• 影响因子: 3.3
• 作者: Z. Hugonin;M. Johnsson;S. Lidin;D. Wulferding;P. Lemmens;R. K. Kremer
• 通讯作者: R. K. Kremer