We report experimental temperature and concentration dependences of the natural spin relaxation time of superparamagnetic Fe₃O₄ and hemozoin nanocrystals. We recorded the ¹H-NMR spectrum of 0.5% benzene dissolved in CS₂ in function of superparamagnetic particle concentration and temperature, interpreting the 7.261±0.002 ppm benzene line broadening. Our model for the line broadening includes natural, hyperfine magnetic dipole-dipole, and contact hyperfine contributions. The latter arises due to exchange interaction between benzene molecules and suspended nanoparticles. Estimated frequency of fluctuation in the 1 cm³ sample volume is in the 10⁷ Hz scale. Estimated natural electron spin-lattice relaxation frequencies of the super[aramagnetic nanocrystals using frequency of fluctuations, and developed theoretical model applied to analysis of experimental data are in good agreement between each other Thus developed in the present study approach can be used for study of fluctuations and natural spin-lattice relaxation frequencies in different medias.

中文翻译：

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Fe ₃ O ₄和血红蛋白超顺磁性纳米晶体自旋弛豫时间的温度依赖性

我们报告了实验温度和浓度的超顺磁性Fe ₃ O ₄和血红蛋白纳米晶体的自然自旋弛豫时间的依赖性。我们记录了溶解在CS ₂中的0.5％苯的¹ H-NMR谱图，它是超顺磁性颗粒浓度和温度的函数，解释了7.261±0.002 ppm的苯线展宽。我们的线展宽模型包括自然的，超精细的磁偶极-偶极子和接触超精细的贡献。后者是由于苯分子和悬浮的纳米颗粒之间的交换相互作用而产生的。1 cm ³样品体积中的波动估计频率为10 ⁷Hz刻度。利用涨落频率估计超顺磁性纳米晶体的自然电子自旋晶格弛豫频率，并建立了用于实验数据分析的理论模型，两者相互吻合，因此，本研究方法的发展可用于研究涨落不同介质中的自然自旋晶格弛豫频率。