Munoz-Menendez Cristina, Serantes David, Ruso Juan M, Baldomir Daniel
Instituto de Investigacións Tecnolóxicas and Departamento de Física Aplicada, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Phys Chem Chem Phys. 2017 Jun 7;19(22):14527-14532. doi: 10.1039/c7cp01442b.
In the context of using magnetic nanoparticles for heat-mediated applications, the need of an accurate knowledge of the local (at the nanoparticle level) heat generation in addition to the usually studied global counterpart has been recently highlighted. Such a need requires accurate knowledge of the links among the intrinsic particle properties, system characteristics and experimental conditions. In this work we have investigated the role of the particles' anisotropy polydispersity in relation to the amplitude (H) of the AC magnetic field using a Monte Carlo technique. Our results indicate that it is better to use particles with large anisotropy for enhancing global heating, whereas for achieving homogeneous local heating it is better to use lower anisotropy particles. The latter ensures that most of the system undergoes major-loop hysteresis conditions, which is the key-point. This is equivalent to say that low-anisotropy particles (i.e. with less heating capability) may be better for accurate heat-mediated applications, which goes against some research trends in the literature that seek for large anisotropy (and hence heating) values.
在将磁性纳米颗粒用于热介导应用的背景下，除了通常研究的整体热生成情况外，最近还强调了准确了解局部（纳米颗粒层面）热生成的必要性。这种需求需要准确了解内在颗粒特性、系统特征和实验条件之间的联系。在这项工作中，我们使用蒙特卡罗技术研究了颗粒各向异性多分散性与交流磁场振幅（H）之间的关系。我们的结果表明，为了增强整体加热，最好使用具有大各向异性的颗粒，而要实现均匀的局部加热，最好使用较低各向异性的颗粒。后者确保系统的大部分处于主回线磁滞条件，这是关键点。这相当于说，低各向异性颗粒（即加热能力较低）可能更适合精确的热介导应用，这与文献中一些寻求大各向异性（从而高加热）值的研究趋势相悖。
