powerpointプレゼンテーション -v5のesrにおける吸収強度の温度依存性.pptVIP

ESR Intensity and Anisotropy of Nanoscale Molecular Magnet V15 IIS, U. Tokyo, Manabu Machida RIKEN, Toshiaki Iitaka Dept. of Phys., Seiji Miyashita Nanoscale Molecular Magnet V15 Outline of The Talk Hamiltonian and Intensity Difficulty Our New Method DCEM (1) DCEM (2) Comparison with Experiment- Temperature Dependence of - With and Without DM Effect of DM at Low Temperatures Triangle Model and Its Energy Levels Intensity Ratio of Triangle Model Summary * Fa3-4 (LT1175) August 12, 2005, Florida, USA (rs.fr/) Vanadiums provide fifteen 1/2 spins. [A. Mueller and J. Doering (1988)] Dzyaloshinsky-Moriya (DM) interaction? A new O(N) algorithm for ESR. Temperature dependence of ESR intensity. We reproduce the experimental data. The effect of DM is not clearly seen. ESR intensity at very low temperatures. The intensity is prominently affected by DM. The deviation due to DM is estimated as Part I Part II – Its computation time is of (e.g. S. Miyashita et al. (1999)) – Direct diagonalization requires memory of difficult! DCEM (The Double Chebyshev Expansion Method) Speed and memory of O(N). Random vector and Chebyshev polynomial. No systematic error. The scheme of time evolution is improved  from BWTDM[T. Iitaka and T. Ebisuzaki, PRL (2003)]. Random phase vector Chebyshev polynomial expansions of the thermal and time-evolution operators. small w [Y.Ajiro et al. (2003)] Our calculation Experiment SIM(8): Intensity by the lowest eight levels. With DM Without DM Intensity ratio Calculated by SIM(8) (the lowest eight levels). : a 1/2 spin Produces energy levels almost equal to those of V15. At zero temperature up to the first order of D Temperature dependence of ESR intensity Intensity ratio at ultra-cold limit Intensity ratio at weak fields (Mz=1/2) deviates from 1 due to DM interaction. The deviation is given by M. M., T. Iitaka, and S. Miyashita, J. Phys. Soc. Jpn. Suppl. 74 (2005) 107 (cond-mat/0501439). M. M., T. Iitaka, and S. Miyashita, in pre