Polarimetric neutron spin echo spectroscopy for the study of magnetic relaxation mechanism

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K20601
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: The University of Tokyo (2021); Kyoto University (2019-2020)
• Principal Investigator: Oda Tatsuro 東京大学, 物性研究所, 助教 (70782308)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 中性子散乱 / 中性子スピンエコー / 偏極中性子 / スピン偏極解析 / 磁性ナノ粒子 / 磁気緩和

Outline of Final Research Achievements

A combination of neutron spin echo spectroscopy and spin polarimetry was studied to establish a spectroscopic method that distinguishes different kinetic modes related to magnetism. Specifically, we analyzed the dynamics of magnetic relaxation in an iron oxide nanoparticles dispersed in solution (magnetic fluid) by neutron spin echo measurements separating spin flip scattering and nuclear scattering. Neutron beam experiments were performed at the BL06 neutron resonance spin echo spectrometer of the Material and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). We analyzed the small angle neutron scattering profiles and spin-echo signals depending on the polarity of a helium spin filter and discuss the effects on the spin echo signal caused by different relaxation modes.

Free Research Field

中性子光学

Academic Significance and Societal Importance of the Research Achievements

多くの物質のダイナミクスは様々な運動モードを反映したものであり，これらが混在した系を観測することになる．このような複雑な運動状態をモデル化し，系統的に理解するために，異なる運動モードを識別したダイナミクス測定が必要とされる．本研究によって開発された分光手法は，磁性に関する運動モードを抽出したダイナミクス測定につながる．