Suchergebnisse

Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements. We show an experimental study in the well-known Py/Pt system by using a coplanar waveguide (CPW). Results obtained demonstrate that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line. A progressive reduction of this width evidences that SRE contribution to the measured transverse voltage signal becomes negligibly small for sample width below 200 μm. A numerical solution of the Maxwell equations in the CPW-sample setup, by using the Landau-Lifshitz equation with the Gilbert damping term (LLG) as the constitutive equation of the media, and with the proper set of boundary conditions, confirms the obtained experimental results. ; We acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through Severo Ochoa Program (CEX2019-000917-S), RTI2018-099960-B-I00 and funding from the European Union Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 645658 (DAFNEOX Project) and FEDER Program. CF thanks Prof. M. Kostylev for fruitful communications. ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000917-S). ; Peer reviewed

Complex oxide thin films grown by using chemical methods are of strong interest because of their low-cost, environment friendly fabrication and easy scalability. However, their introduction in spintronic applications or magnetic devices is still scarce mainly because of concerns regarding their interfacial quality. Here, we report on the preparation by polymer-assisted-deposition (PAD) of epitaxial La0.92MnO3 (LMO) thin films. We demonstrate that ferromagnetic conducting LMO thin films with smooth surfaces (rms ∼ 0.2 nm) can be prepared by PAD. By means of temperature-dependent broadband ferromagnetic resonance (FMR), we show that the LMO film exhibits a four-fold in-plane anisotropy, with [110] being the easy in-plane axis, compatible with strain release from the rhombohedral bulk phase. It has also been found that the isotropic Gilbert damping, α, determined from the broadening of the FMR linewidth, does not show a relevant extrinsic contribution and it exhibits an intraband-like temperature dependence, i.e. it increases as temperature decreases. By capping LMO thin films with a 10 nm thick Pt layer deposited ex situ, damping is substantially enhanced, from a value at 150 K of αLMO ∼ 1 × 10−2 for the bare LMO film to αLMO+Pt ∼ 2.5 × 10−2 for the Pt capped film. This strong increase of magnetic damping is indicative of the transfer of spin momentum from LMO to the Pt layer by spin pumping. Our results demostrate that LMO films grown by PAD may be used as efficient spin source systems in heterostructures for spintronic devices. ; We acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through Severo Ochoa (SEV-2015-04969), HETEROCS (MAT2015-71664-R), SUMATE (RTI2018-095853-B-C21) and SPINCURIOX (RTI2018-099960-B-I00) projects cofinanced by the European Regional Development Fund. This project has received funding from the European Union through the Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 645658 (DAFNEOX Project) and through the FEDER Program. Hailin Wang acknowledges financial support from the China Scholarship Council (CSC). This work has been performed in the framework of the PhD programme in Materials Science of the Universitat Autònoma de Barcelona, through the China Scholarships Council (CSC)/Universitat Autònoma de Barcelona (UAB) Joint Scholarship. Authors thank Dr B. Bozzo and F. J. Campos for their technical support during magnetic and X-ray diffraction measurements. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). ; Peer reviewed

Spin to charge conversion process in a broad range of temperatures is studied in La0.92MnO3/Pt bilayers prepared by polymer-assisted deposition (PAD). It is shown that an excellent LMO/Pt interface can be obtained in spite of using ex situ deposition of the Pt layer. The values obtained for the effective spin-mixing conductance, g↑↓eff = 0.76 × 1015 cm−2, suggest that significant spin transport across the LMO/Pt interface could be achieved. Spin pumping experiments generate a transversal voltage signal VISHE, due to spin to charge conversion via inverse spin Hall effect, that has been detected down to about 100 K with values of the spin-Hall angle, θSH, of about 2.5%, slightly decreasing on reducing temperature in the analyzed temperature range. These results indicate that LMO is a promising perovskite building block for all-oxide multifunctional high-frequency spintronics devices and that PAD technique provides oxide epitaxial thin films of good quality adequate for spintronic applications. ; We acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through Severo Ochoa (CEX2019-000917-S), and SPINCURIOX (RTI2018-099960-BI00) and AMONANO (PID2020-112914RB-I00) projects co-financed by the European Regional Development Funds. AMONANO also received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 823717-ESTEEM3. Hailin Wang acknowledges financial support from the China Scholarship Council (CSC). ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000917-S). ; Peer reviewed