Structural, electron transportation and magnetic behavior transition of metastable FeAlO granular films.
Structural, electron transportation and magnetic behavior transition of metastable FeAlO granular films.
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亚稳态 FeAlO 颗粒薄膜的结构、电子传输和磁行为转变
DOI：
10.1038/srep24410
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发表时间：
2016-04-14
影响因子：
4.6
通讯作者：
Yan M
中科院分区：
文献类型：
--
作者：
Bai G;Wu C;Jin J;Yan M
金属-绝缘体颗粒膜在微波应用中具有重要的技术意义。由于绝缘非磁性和金属磁性组分的平衡，同时获得高电阻率和大饱和磁化强度一直具有挑战性。用脉冲激光沉积法制备了满足这两种要求的FeAlO颗粒膜。尽管Fe含量（0.77）超过了逾渗阈值，但沉积态薄膜仍具有3700 μΩ·cm的高电阻率和负温度系数。这源于其独特的微观结构，包含嵌入在Al 2 O3网络的非晶Fe纳米颗粒。通过优化退火条件，获得了饱和磁化强度（>1.05 T）、电阻率（>1200 μΩ·cm）和Δf（>3.0 GHz）等优良的上级电磁性能。在673 K退火后，观察到Al 2 O3作为夹杂物聚集在结晶的Fe（Al）基体中的相分离，导致金属样电阻率。我们提供了一种可行的方法来实现高电阻率和大的饱和磁化强度的FeAlO薄膜与占主导地位的金属成分，并表明，微观结构可以调整所需的性能。
Metal-insulator granular film is technologically important for microwave applications. It has been challenging to obtain simultaneous high electrical resistivity and large saturation magnetization due to the balance of insulating non-magnetic and metallic magnetic components. FeAlO granular films satisfying both requirements have been prepared by pulsed laser deposition. The as-deposited film exhibits a high resistivity of 3700 μΩ∙cm with a negative temperature coefficient despite that Fe content (0.77) exceeds the percolation threshold. This originates from its unique microstructure containing amorphous Fe nanoparticles embedded in Al2O3network. By optimizing the annealing conditions, superior electromagnetic properties with enhanced saturation magnetization (>1.05 T), high resistivity (>1200 μΩ∙cm) and broadened Δf(>3.0 GHz) are obtained. Phase separation with Al2O3aggregating as inclusions in crystallized Fe(Al) matrix is observed after annealing at 673 K, resulting in a metallic-like resistivity. We provide a feasible way to achieve both high resistivity and large saturation magnetization for the FeAlO films with dominating metallic component and show that the microstructure can be tuned for desirable performance.