Spin mixing conductance (SMC) at the ferromagnetic/non-magnetic material (FM/NM) interface governs the transport efficiency of the spin current. A high level of SMC is crucial for efficient spin injection and spin manipulation. Here, we report a reliable way to enhance the SMC at the FM/NM interface by rare-earth doping in the NM layer. As evidenced by the decreased saturation magnetization in permalloy (Py)/Cu–Nd structures, an induced magnetism in Nd is proposed, which is likely to be antiferromagnetically coupled to Py at the interface. By changing the doping content of Nd, the Py/Cu–Nd interface can be well designed, which gives rise to an effective tuning of the SMC from 0.37 × 1015 to 16.26 × 1015 cm−2. Such a tuning effect of SMC is suppressed by inserting a Cu spacer, demonstrating the key role of the antiferromagnetically coupled interface to the improved SMC. Our results highlight the significance of rare-earth materials in spin transport, expanding the design capability of energy-efficient spintronic devices.
In this work, using a Permalloy film and a superconducting cavity, we highlight the unique dispersion in the microwave transmission properties of the magnon–photon coupled system in the Purcell regime, in which the modulation of the coupled system can be achieved by varying the magnon dissipation rate. It is demonstrated that decreasing the magnon dissipation rate can lead to an enhancement in magnon–photon coupling. By applying a direct current into the Permalloy/platinum bilayer, we achieve modulation of the coupling in the Purcell regime. The magnon–photon coupling is enhanced with the increasing current, which is related to the decrease in the magnon dissipation rate due to the thermal effect of the current. In addition, we establish an approach to obtain the coupling strength from the coupled microwave photon dispersion and linewidth. The electrical control of the Permalloy-superconducting cavity coupled system will play an important role in manipulating integrated hybrid magnon–photon devices.
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