Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userDynamic pinning at a Py/Co interface measured using inductive magnetometry
99
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Broadband FMR responses for metallic single-layer and bi-layer magnetic films with total thicknesses smaller than the microwave magnetic skin depth have been studied. Two different types of microwave transducers were used to excite and detect magnetization precession: a narrow coplanar waveguide and a wide microstrip line. Both transducers show efficient excitation of higher-order standing spin wave modes. The ratio of amplitudes of the first standing spin wave to the fundamental resonant mode is independent of frequency for single films. In contrast, we find a strong variation of the amplitudes with frequency for bi-layers and the ratio is strongly dependent on the ordering of layers with respect to a stripline transducer. Most importantly, cavity FMR measurements on the same samples show considerably weaker amplitudes for the standing spin waves. All experimental data are consistent with expected effects due to screening by eddy currents in films with thicknesses below the microwave magnetic skin depth. Finally, conditions for observing eddy current effects in different types of experiments are critically examined.
rate research
Read More
The spin dependent reflection at the interface is the key element to understand the spin transport. By completely solving the scattering problem based on first principles method, we obtained the spin resolved reflectivity spectra. The comparison of our theoretical results with experiment is good in a large energy scale from Fermi level to energy above vacuum level. It is found that interfacial distortion is crucial for understanding the spin dependence of the phase gain at the Cu$|$Co interface. Near the Fermi level, image state plays an important role to the phase accumulation in the copper film.
Spin-orbit torques due to interfacial Rashba and spin Hall effects have been widely considered as a potentially more efficient approach than the conventional spin-transfer torque to control the magnetization of ferromagnets. We report a comprehensive study of spin-orbit torque efficiency in Ta(O)/Ni81Fe19 bilayers by tuning low-oxidation of b{eta}-phase tantalum, and find that the spin Hall angle {theta}DL increases from ~ -0.18 of the pure Ta/Py to the maximum value ~ -0.30 of Ta(O)/Py with 7.8% oxidation. Furthermore, we distinguish the efficiency of the spin-orbit torque generated by the bulk spin Hall effect and by interfacial Rashba effect, respectively, via a series of Py/Cu(0-2 nm)/Ta(O) control experiments. The latter has more than twofold enhancement, and even more significant than that of the former at the optimum oxidation level. Our results indicate that 65% enhancement of the efficiency should be related to the modulation of the interfacial Rashba-like spin-orbit torque due to oxygen-induced orbital hybridization cross the interface. Our results suggest that the modulation of interfacial coupling via oxygen-induced orbital hybridization can be an alternative method to boost the change-spin conversion rate.
Thin film synthesis methods developed over the past decades have unlocked emergent interface properties ranging from conductivity to ferroelectricity. However, our attempts to exercise precise control over interfaces are constrained by a limited understanding of growth pathways and kinetics. Here we demonstrate that shuttered molecular beam epitaxy induces rearrangements of atomic planes at a polar / non-polar junction of LaFeO$_3$ (LFO) / $n$-SrTiO$_3$ (STO) depending on the substrate termination. Surface characterization confirms that substrates with two different (TiO$_2$ and SrO) terminations were prepared prior to LFO deposition; however, local electron energy loss spectroscopy measurements of the final heterojunctions show a predominantly LaO / TiO$_2$ interfacial junction in both cases. Ab initio simulations suggest that the interfaces can be stabilized by trapping extra oxygen (in LaO / TiO$_2$) and forming oxygen vacancies (in FeO$_2$ / SrO), which points to different growth kinetics in each case and may explain the apparent disappearance of the FeO$_2$ / SrO interface. We conclude that judicious control of deposition timescales can be used to modify growth pathways, opening new avenues to control the structure and properties of interfacial systems.
To explore the origin of the Fermi level pinning in germanium we investigate the Ge(001) and Ge(001):H surfaces. The absence of relevant surface states in the case of Ge(001):H should unpin the surface Fermi level. This is not observed. For samples with donors as majority dopants the surface Fermi level appears close to the top of the valence band regardless of the surface structure. Surprisingly, for the passivated surface it is located below the top of the valence band allowing scanning tunneling microscopy imaging within the band gap. We argue that the well known electronic mechanism behind band bending does not apply and a more complicated scenario involving ionic degrees of freedom is therefore necessary. Experimental techniques involve four point probe electric current measurements, scanning tunneling microscopy and spectroscopy.
A d-orbital electron has an anisotropic electron orbital and is a source of magnetism. The realization of a 2-dimensional electron gas (2DEG) embedded at a LaAlO3/SrTiO3 interface surprised researchers in materials and physical sciences because the 2DEG consists of 3d-electrons of Ti with extraordinarily large carrier mobility, even in the insulating oxide heterostructure. To date, a wide variety of physical phenomena, such as ferromagnetism and the quantum Hall effect, have been discovered in this 2DEG systems, demonstrating the ability of the d-electron 2DEG systems to provide a material platform for the study of interesting physics. However, because of both ferromagnetism and the Rashba field, long-range spin transport and the exploitation of spintronics functions have been believed difficult to implement in the d-electron 2DEG systems. Here, we report the experimental demonstration of room-temperature spin transport in the d-electron-based 2DEG at a LaAlO3/SrTiO3 interface, where the spin relaxation length is ca. exceeding 200 nm. Our finding, which counters the conventional understandings to d-electron 2DEGs, opens a new field of d-electron spintronics. Furthermore, this work highlights a novel spin function in the conductive oxide system.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
