基于稀释反铁磁增强交换偏置效应调控软磁金属薄膜微波磁性的研究

交换偏置效应可有效提高软磁金属薄膜的有效磁各向异性场及铁磁共振频率，而现有研究中其调变手段局限于铁磁层厚度调制，且忽视了对矫顽力和阻尼的影响。对此，本项目提出基于稀释反铁磁增强交换偏置效应调控软磁金属薄膜的微波磁性。首先，将针对软磁薄膜的微波应用，研究稀释反铁磁对交换偏置的影响规律，实现室温下交换偏置的增强，同时基于交换偏置模型体系，精确控制界面、非磁掺杂等因素，探讨反铁磁稀释效应的影响机制；其次，将研究矫顽力随反铁磁稀释和交换偏置的变化规律，总结三者之关联，揭示矫顽力升高与交换偏置机制的差异；再次，通过微波表征及磁化动力学拟合分析，揭示磁各向异性，探讨阻尼因子的变化规律及来源机制。在此基础上，通过稀释反铁磁增强交换偏置效应实现软磁薄膜微波共振频率的大幅提升，以及对矫顽力和阻尼的抑制调控。本项目研究成果对于交换偏置机制的进一步揭示以及软磁金属薄膜在微波集成器件领域的推广应用具有重要意义。

Exchange bias effect has been employed to increase the effective magnetic anisotropy and ferromagnetic resonance frequency of soft magnetic metallic thin films. However, the present related studies are focused on the thickness effect of ferromagnetic layers, and overlook the influences on coercivity and damping. In this proposal, we propose that the microwave characteristics of soft magnetic metallic thin films should be effectively tuned by the enhanced exchange bias effect with diluted antiferromagnets. Firstly, aimed at the microwave applications of soft magnetic thin films, we will investigate and obtain the rules by which the dilution of antiferromagnets affects the exchange bias, and realize the enhancement of exchange bias at room temperature. We will also design and deposit exchange-bias bilayers as a model system, with precisely controlled interfaces and dilutions with nonmagnetic elements, to further study and clarify the influence mechanisms by diluted antiferromagnets. Secondly, the dependences of coercivity on the dilution of antiferromagnets and exchange bias will be studied, and their correlation will be emphasized. The different origins between the increase of coercivity and exchange bias will be revealed. Thirdly, by microwave characterizations and the fitting analysis based on magnetization dynamics, we will differentiate the magnetic anisotropies, and investigate the dependences and origins of microwave damping. On the basis of these studies, we will realize a remarkable increase of microwave resonance frequency of soft magnetic thin films by enhanced exchange bias effect with diluted antiferromagnetic layers, and effective controls of coercivity and damping. The results of this project are valuable for the understanding of exchange bias effect, and significant for the future applications of soft magnetic metallic thin films among microwave IC devices.