Single-phase Ni-Cu ferrite nanoparticles have been prepared by sol–gel method and exposed using an Am-Be source for time periods of one and two months. The effects of irradiation on structure and magnetic properties of prepared nanoparticles are investigated by X-ray diffraction, positron annihilation spectroscopy and vibrating sample magnetometer. The X-ray measurements showed that unirradiated and irradiated samples have cubic spinel structure and variation of structural parameters with irradiation is nonuniform. The positron annihilation measurements showed that the main effect of irradiation on samples is variation in momentum distribution of core electrons in metallic cations. The magnetic measurements represent that irradiation cause an increase in saturation magnetization and a decrease in coercivity. The increase in saturation magnetization is attributed to cation redistribution because of atomic displacement. The decrease in coercivity is attributed to the variation of magnetocrystalline anisotropy constant due to the effect of irradiation on the core electrons of cations.

单相 Ni-Cu 铁氧体纳米颗粒已通过溶胶-凝胶法制备，并使用 Am-Be 源暴露一两个月。通过X射线衍射、正电子湮没光谱和振动样品磁强计研究了辐照对制备的纳米粒子结构和磁性能的影响。X射线测量表明，未辐照和辐照样品均具有立方尖晶石结构，结构参数随辐照的变化不均匀。正电子湮没测量表明，辐照对样品的主要影响是金属阳离子中核心电子动量分布的变化。磁测量表明辐照导致饱和磁化强度增加和矫顽力降低。饱和磁化强度的增加归因于原子位移引起的阳离子重新分布。矫顽力的降低是由于辐照对阳离子核心电子的影响导致磁晶各向异性常数的变化。