Nickel ferrite nanoparticles were subjected to mechanochemical activation for ball milling times ranging from 0 to 12 h. The milling was performed with and without the addition of equimolar concentrations of graphene nanoparticles. Characterization of resulting nano-powders was undertaken by Mӧssbauer spectroscopy and magnetic measurements. The hyperfine magnetic field was studied as function of milling time for octahedral and tetrahedral sites. An additional quadrupole split doublet represented the occurrence of superparamagnetic particles in the as-obtained and milled specimens. A new phase was obtained in the graphene-milled set of samples, which could be assigned to carbon-rich particles. The degree of inversion and canting angle were derived from the Mӧssbauer measurements and studied as function of ball milling time. The degree of inversion was found to decrease with milling time, especially for the set without graphene and evidenced a transition from inverse to normal spinels. The canting angle decreased with time for the graphene milled nanoparticles. The recoilless fraction was determined as function of milling time and was consistent with the observation – for the first time in literature – of a distribution of recoilless fractions in the studied specimens. The saturation magnetization, remanence magnetization and coercive field were derived from the hysteresis loops, recorded at 5 K and 5 T. The zero-field-cooling-field-cooling measurements were obtained in a magnetic field of 200 Oe and the blocking temperature was determined. Our results show new features of the behavior of nickel ferrite nanoparticles under mechanochemical activation with and without graphene.

对镍铁氧体纳米粒子进行机械化学活化，球磨时间为0到12小时。在添加和不添加等摩尔浓度的石墨烯纳米颗粒的情况下进行研磨。通过Msssbauer光谱学和磁性测量对所得的纳米粉末进行表征。研究了超精细磁场与八面体和四面体位点铣削时间的关系。附加的四极分裂双峰表示在获得和研磨的样品中出现超顺磁性颗粒。在石墨烯磨碎的样品集中获得了一个新相，可以将其分配给富碳颗粒。倒角和倾斜角是根据Msssbauer测量得出的，并作为球磨时间的函数进行研究。发现倒置度随研磨时间而降低，特别是对于没有石墨烯的倒置，并证明了从倒置尖晶石到正常尖晶石的转变。对于石墨烯研磨的纳米颗粒，倾斜角随时间减小。无后坐力分数被确定为研磨时间的函数，这与文献中首次观察到的无后坐力分数在研究样本中的观察结果一致。从磁滞回线导出饱和磁化强度，剩磁强度和矫顽场，并记录在5 K和5 T下。在200 Oe的磁场中获得零场冷却场冷却测量值，并确定阻塞温度。