Nanoparticles with general formula CoFe_2-xRE_xO₄ (RE = Yb, Dy, Gd; x = 0.0–0.3) were synthesized by the co-precipitation and heat treated for potential application in magnetic hyperthermia. The influence of RE doping on structural, magnetic and thermal properties has been investigated. The RE cations enter the spinel lattice as detected by X-ray diffraction. Thermal treatment leads to thermodynamically stable and relaxed single-phase spinel structures only for lower RE content, x = 0.01–0.05. The annealed samples present higher mass magnetization values up to 83 Am²/kg. In the case of annealed samples saturation magnetization decreases linearly from 83 Am²/kg (x = 0.01) to about 60 Am²/kg (x = 0.30). Thermal treatment induces a reduction in coercivity from 60 to 100 mT for as-prepared samples to 18–33 mT for annealed samples. Heating efficiency, i.e., Specific Loss Power of all samples has been studied using both magnetometric and calorimetric method to examine the energy loss mechanisms.

Ñ anoparticles与通式的CoFe _2-X RE _X ø ₄（RE =镱，镝，钆; X = 0.0-0.3）通过共沉淀合成并在磁热疗潜在应用热处理。研究了稀土掺杂对结构，磁和热性能的影响。通过X射线衍射检测，RE阳离子进入尖晶石晶格。热处理仅在较低的RE含量（x = 0.01-0.05）下产生热力学稳定且松弛的单相尖晶石结构。退火的样品呈现更高的质量磁化值，最高为83 Am ² / kg。在退火样品的情况下，饱和磁化强度从83 Am ² / kg（x = 0.01）线性降低至约60 Am² / kg（x = 0.30）。热处理可将矫顽力从制备样品的60 mT降低到100 mT，将退火样品的矫顽力降低到18-33 mT。已经使用磁力法和量热法研究了加热效率，即所有样品的比损失功率，以研究能量损失的机理。