Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, 730000, Lanzhou, People's Republic of China.
Nanoscale Res Lett. 2010 Apr 24;5(7):1107-10. doi: 10.1007/s11671-010-9609-y.
A series of nano-granular films composed of magnetic metal (Fe65Co35) granules with a few nanometers in size and semiconductor oxide (ZnO) have been fabricated by a magnetron sputtering method, and excellent soft magnetic properties have been achieved in a wide metal volume fraction (x) range for as-deposited samples due to the exchange coupling between FeCo granules (a ferromagnetic interaction in nano-scale). In a wide range (0.53 <x < 0.71), the films exhibit coercivity HC not exceeding 15 Oe, along with high resistivity. Especially for the sample with x = 0.67, coercivities in hard and easy axes are 1.43 and 7.08 Oe, respectively, 4πMS = 9.85 kg, and ρ reaches 2.06 × 103 μΩ cm. The dependence of complex permeability μ = μ' - jμ″ on frequency shows that the real part μ' is more than 100 below 1.83 GHz and that the ferromagnetic resonance frequency reaches 2.31 GHz, implying the promising for high frequency application. The measured negative temperature coefficient of resistivity reveals that may be the weak localized electrons existing in samples mediate the exchange coupling.
采用磁控溅射法制备了由粒径为数纳米的磁性金属（Fe65Co35）颗粒和半导体氧化物（ZnO）组成的一系列纳米颗粒薄膜。由于 FeCo 颗粒之间的交换耦合（纳米尺度上的铁磁相互作用），在沉积态样品的宽金属体积分数（x）范围内实现了优异的软磁性能。在很宽的范围内（0.53 < x < 0.71），薄膜的矫顽力 HC 不超过 15 Oe，同时具有高电阻率。特别是对于 x = 0.67 的样品，硬轴和软轴的矫顽力分别为 1.43 和 7.08 Oe，4πMS = 9.85 kg，ρ 达到 2.06 × 103 μΩ cm。复数磁导率 μ = μ' - jμ″随频率的变化表明，在 1.83 GHz 以下，实部 μ' 大于 100，铁磁共振频率达到 2.31 GHz，这意味着在高频应用方面具有很大的潜力。测量得到的电阻率负温度系数表明，可能是样品中存在的弱局域电子介导了交换耦合。
