Study on the Origin of the Large Field Induced Magnetic Anisotropy of Nano-granular Soft Magnetic films and Its Applications

软磁金属-绝缘体纳米颗粒薄膜如（Fe、Co、Ni金属及其合金）-（Al、Mg、RE氧化物、氮化物和氟化物）纳米颗粒薄膜由于具有高的电阻率（ρ）、磁矩（Bs）和磁各向异性场（Hk）而被认为是薄膜型高频磁感芯材料。我们已经发现，Co基薄膜含有超过10原子。% Pd在保持大的ρ和Bs的情况下表现出大于200 Oe的巨大Hk。的Hk是可控的大小，以及在其单轴方向通过调整场退火条件。大的Hk带来谐振频率（fr）的显著增加，直到GHz区域。在本计画中，我们研究了纳米颗粒软磁薄膜的磁各向异性（Ku）与场退火条件和成分的关系，并从结构实验上探讨了纳米颗粒Co-Pd基薄膜的大Ku的来源，并讨论了这些薄膜的应用。准备了电影 ...更多信息 艾德通过射频反应磁控溅射与Ar+O_2气体。在振动样品磁强计和扭矩磁强计上进行了磁性测量。金属-绝缘体型纳米颗粒软磁薄膜的Ku特性可以概括为四个方面：1）在Co-Pd-Si-O薄膜中发现了非常大的Ku值，可达1.5 × 10^5erg/cc，2）薄膜的Ku值归因于磁场诱导的各向异性，3）发现了独特的材料依赖性，即Co-Pd基>Co基>Fe基薄膜，（4）（FeCo）-Al-O薄膜中Ku的反常成分依赖性不能用原子对有序化来解释。高分辨电子显微镜和小角X射线散射的结构研究揭示了Co-Pd-Si-O薄膜的Ku的一个模型。Co-Si-Pd-O薄膜的大Ku值归因于颗粒间和颗粒与基体间界面原子的重新排列，导致Co-Pd被低对称性原子环境所包围而产生强的各向异性。颗粒金属的晶体磁各向异性也可能与膜中Ku的大小有关。这些软磁薄膜将成为几GHz范围内电感器和Transformer等磁芯材料的有力候选者。在fr附近具有很大的磁导率，是一种适合于GHz频段电磁噪声抑制的材料。少

Soft magnetic metal-insulator nano-granular thin films such as (Fe, Co, Ni metals and their alloys)-(Al, Mg, RE oxides, nitrides and fluorides) are considered as the thin film-type high frequency magnetic inductive core materials, because of their high electrical resistivity (ρ), magnetic moments (Bs) and magnetic anisotropy field (Hk). We have found that the Co based films containing more than 10 at. % Pd exhibit huge Hk more than 200 Oe in keeping large ρ and Bs. The Hk is controllable in magnitude as well as in its uniaxial direction by adjusting of field-annealing conditions. A large Hk brings remarkable increase in the resonance frequency (fr) up to GHz region. In this project, we investigate the dependence of magnetic anisotropy (Ku) on field-annealing condition and composition for nano-granular soft magnetic films, and examine the origin of a large Ku of nano-granular Co-Pd based films from the structural experiments and discuss the applications of these films. Films were prepar … More ed by rf reactive magnetron sputtering with Ar+O_2 gases. Magnetic measurements were conducted on both a vibrating sample magnetometer and a torque magnetometer. The features of the Ku for metal-insulator type nano-granular soft magnetic films can be summarized into four things; 1) extraordinary large magnitude of Ku, as large as 1.5x 10^5 erg/cc is found in Co-Pd-Si-O films, 2) Ku of the films is attributed to a magnetically field induced anisotropy, 3) unique materials dependence of Ku is found as Co-Pd based>Co based>Fe based films, and 4) anomalous compositional dependence of Ku in (FeCo)-AI-O films cannot be explained in terms of the atom pair ordering. Structural investigations by HREM and SAXS have revealed a model to explain the Ku of Co-Pd-Si-O films. A large Ku of Co-Si-Pd-O films is attributed to a realignment of atoms at interfaces between granules and between granule and matrix, resulting in a strong anisotropy due to Co-Pd surrounded by a low symmetrical atomic environment. A crystal magnetic anisotropy of granule metals may also be related to the magnitude of Ku in the films. These soft magnetic thin films will be a strong candidate for magnetic core materials of inductor and transformer and so on at a few GHz range. And their large permeability near fr suggests that these films are a suitable for the electromagnetic noise suppression materials at GHz band. Less