Powell Camilah D, Lounsbury Amanda W, Fishman Zachary S, Coonrod Christian L, Gallagher Miranda J, Villagran Dino, Zimmerman Julie B, Pfefferle Lisa D, Wong Michael S
Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Houston, TX, USA.
Nano Converg. 2021 Mar 9;8(1):8. doi: 10.1186/s40580-021-00258-7.
Nano-sized hematite (α-FeO) is not well suited for magnetic heating via an alternating magnetic field (AMF) because it is not superparamagnetic-at its best, it is weakly ferromagnetic. However, manipulating the magnetic properties of nano-sized hematite (i.e., magnetic saturation (Ms), magnetic remanence (Mr), and coercivity (Hc)) can make them useful for nanomedicine (i.e., magnetic hyperthermia) and nanoelectronics (i.e., data storage). Herein we study the effects of size, shape, and crystallinity on hematite nanoparticles to experimentally determine the most crucial variable leading to enhancing the radio frequency (RF) heating properties. We present the synthesis, characterization, and magnetic behavior to determine the structure-property relationship between hematite nano-magnetism and RF heating. Increasing particle shape anisotropy had the largest effect on the specific adsorption rate (SAR) producing SAR values more than 6 × greater than the nanospheres (i.e., 45.6 ± 3 W/g of α-FeO nanorods vs. 6.89 W/g of α-FeO nanospheres), indicating α-FeO nanorods can be useful for magnetic hyperthermia.
纳米尺寸的赤铁矿（α-Fe₂O₃）不太适合通过交变磁场（AMF）进行磁热效应，因为它不是超顺磁性的——充其量只是弱铁磁性。然而，操控纳米尺寸赤铁矿的磁性能（即磁饱和强度（Ms）、剩磁（Mr）和矫顽力（Hc））可使其在纳米医学（即磁热疗）和纳米电子学（即数据存储）中发挥作用。在此，我们研究尺寸、形状和结晶度对赤铁矿纳米颗粒的影响，以通过实验确定导致射频（RF）加热性能增强的最关键变量。我们展示了合成、表征及磁行为，以确定赤铁矿纳米磁性与射频加热之间的结构-性能关系。增加颗粒形状各向异性对比吸收率（SAR）的影响最大，所产生的SAR值比纳米球高出6倍多（即α-Fe₂O₃纳米棒的SAR为45.6±3W/g，而α-Fe₂O₃纳米球的SAR为6.89W/g），这表明α-Fe₂O₃纳米棒可用于磁热疗。
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