Soft-magnetic nickel ferrite (NiFe₂O₄) nanoparticles were synthesized via solution combustion synthesis (SCS). The influence of the fuel concentration and the post-treatment temperature on the structural and magnetic properties of the samples were studied. The samples produced in a fuel-short regime presented the purest NiFe₂O₄ nanoparticles, with an average diameter of 32 nm. Spinel inversion degree, composition, crystallite size, and surface area were evaluated regarding their influence on the magnetic behavior of the nanoparticles. Interestingly, the magnetic properties of pure NiFe₂O₄ samples remained unaffected even after heat-treated above 900 °C. This result is promising for industrial applications that require magnetic stability over temperature changes. NiFe₂O₄ presented a critical size of 40 nm for single-domain to multi-domain transition. Below 40 nm, the discharge of Ni and α-Fe₂O₃ from the NiFe₂O₄ structure is the main factor influencing the magnetism. Pure NiFe₂O₄ samples treated at different temperatures presented a similar spinel inversion and consequently similar coercivities, approximately 170 Oe.

通过固溶燃烧合成（SCS）合成了软磁性镍铁氧体（NiFe ₂ O ₄）纳米粒子。研究了燃料浓度和后处理温度对样品结构和磁性能的影响。在燃料短缺状态下生产的样品呈现出最纯的NiFe ₂ O ₄纳米颗粒，平均直径为32 nm。评估尖晶石的转化度，组成，微晶尺寸和表面积对它们对纳米粒子磁性行为的影响。有趣的是，纯NiFe ₂ O ₄的磁性即使在高于900°C的温度下进行热处理，样品仍不受影响。对于需要随温度变化而具有磁稳定性的工业应用而言，这一结果很有希望。NiFe ₂ O ₄的临界尺寸为40 nm，用于单畴到多畴的转变。低于40纳米，Ni和α-Fe的放电₂ Ó ₃从由NiFe ₂ ø ₄结构是影响磁性的主要因素。在不同温度下处理的纯NiFe ₂ O ₄样品表现出相似的尖晶石转化率，因此矫顽力相似，约为170 Oe。