The heating characteristics of ferrite nanoparticles are inconsistent due to various factors that affect the optimum particle size required for maximum power dissipation. The heating mechanism of Fe 3 O 4 , MnFe 2 O 4 , and Co 0.5 Fe 2.5 O 4 in the size range 10–40 nm with varying particle size distribution is correlated with the effective specific absorption rate (ESAR). The effective magnetic anisotropy of the ferrite samples determined using electron spin resonance is between 11.8 and 24.8 kJ· m −3 . The thermal profiles of Fe 3 O 4 , MnFe 2 O 4 , and Co 0.5 Fe 2.5 O 4 are probed employing infrared thermography where the measured ESAR is between 1.74 and 3.16 nHm 2 ·kg −1 . The theoretical ESAR of 16.63 and 9.19 nHm 2 ·kg −1 are obtained for the Co substituted Fe 3 O 4 and MnFe 2 O 4 , respectively, for an average size of 40 nm. The analysis of particle size distributions in combination with theoretical estimations gives the percentage of particles contributing to the power dissipation as 80 % for narrow dispersion and 45 % for broad dispersion deviating from the predicted optimum size range. In addition to ascertaining the functioning regime of the linear response theory, an increase in ESAR with decreasing anisotropy energy is observed. The discrepancy between the simulations and experimentations is prudently examined, taking the intrinsic as well as extrinsic parameters into account.

中文翻译：

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对锰铁氧体和钴铁氧体加热特性的洞察

由于影响最大功率耗散所需的最佳粒径的各种因素，铁氧体纳米颗粒的加热特性不一致。Fe 3 O 4 、MnFe 2 O 4 和Co 0.5 Fe 2.5 O 4 的加热机制在10-40 nm 范围内具有不同的粒径分布，与有效比吸收率（ESAR）相关。使用电子自旋共振确定的铁氧体样品的有效磁各向异性介于 11.8 和 24.8 kJ·m -3 之间。Fe 3 O 4 、MnFe 2 O 4 和Co 0.5 Fe 2.5 O 4 的热分布采用红外热成像法探测，其中测得的ESAR 介于1.74 和3.16 nHm 2 ·kg -1 之间。对于平均尺寸为 40 nm 的 Co 取代的 Fe 3 O 4 和 MnFe 2 O 4 ，分别获得了 16.63 和 9.19 nHm 2 ·kg -1 的理论 ESAR。结合理论估计对粒度分布的分析给出了对功率耗散有贡献的颗粒百分比，对于窄分散为 80%，对于偏离预测的最佳尺寸范围的宽分散为 45%。除了确定线性响应理论的功能范围外，还观察到 ESAR 随着各向异性能量的降低而增加。考虑到内在和外在参数，谨慎地检查了模拟和实验之间的差异。除了确定线性响应理论的功能范围外，还观察到 ESAR 随着各向异性能量的降低而增加。考虑到内在和外在参数，谨慎地检查了模拟和实验之间的差异。除了确定线性响应理论的功能范围外，还观察到 ESAR 随着各向异性能量的降低而增加。考虑到内在和外在参数，谨慎地检查了模拟和实验之间的差异。