| The development of new electric devices, especially spintronic devices, has drawn more and more attentions in the academic and industry field. Spin electron can be the carrier of information in spintronic devices of which the core technology relies on how to effectively generate, transmit and detect of spin currents. In this paper, spin pumping and inverse spin Hall effect are employed as the generation and detection method,respectively. From the general theories of LLG equation, General Ohm’s law and spin injection, the formula of the VSRE and VISHE are derivated. On the basis of that, two test methods, involving the rotation of the magnetic field and the inverting of samples during test respectively, are presented to separate the VSRE and VISHE signals. And ferromagnetic resonance and the spin rectification effect test system are established with measurements of the inverse spin Hall effect of samples performed to study the effects of the interface of thin films on spin injection.Firstly, parameters like ferromagnetic resonance linewidth are obtained by vector network analyzer. Compared with the parameters measured by spin rectification method,the results from both the two methods are nearly the same. However, in the method of spin rectification, the signals feature higher signal to noise ratio, better linearity of the signal with simpler and more reliable material parameters through data fitting. A conclusion can be drawn, by comparing the results of NiFe and NiFe/Pt, that ferromagnetic resonance linewidth of bilayer membrane, due to the presence of spin injection, is greater than that in monolayer film system. Besides, in bilayer membrane,symmetrical components in the measured voltage with the linearly varying static magnetic field weights greater than that of monolayer film because of the contribution of ISHE to the symmetrical components.Secondly, from the non-equilibrium spin diffusion, analytical expression of VISHE is deduced, which lead to the proposal of the test method of separating VSRE and VISHE components by changing the external magnetic field angle. The results indicate that the VSRE and VISHE both contribute to the symmetrical components AL, because if the AL is all from ISHE, the spin injection efficiency is about 15.4% higher. Meanwhile,considering the dependence of voltage on the difference of injection direction of spin current, a test method is proposed, which is more convenient and efficiency to separateVSRE and VISHE than the angle-rotation method.Through sweeping-frequency tests, the VSRE and VISHE with the frequency change are only relevant to test fixtures rather than the sample itself. In addition, the amplitude characteristics of bilayer membrane rely on the AL components as the existence of spin injection. As the microwave power increases, VISHE value of the sample goes up linearly.Then, the spin Hall angle, the intrinsic parameter of materials, is calculated, of which the result turns out to be that the spin Hall angle does not change with the frequency varying, indicating that the spin conversion efficiency has a close relation with the sample itself but with nothing to do with the wave frequency.Finally, the influence of the interface with different oxidation time on the spin injection is studied. As a result, with the increase of FM/NM interface oxidation time,both the damping and ferromagnetic resonance linewidth are increasing, and when the oxidation time is 2 h, the spin injection from non-magnetic sample to ferromagnetic sample vanishes. While, the VISHE behaves differently, decreasing with the increase of interface oxidation time. |
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