Using first-principles calculations, we studied Mn 2 RuZ (Z=Al, Ga, Si, Ge) and their heterojunctions with MgO along (001) direction. All these alloys possess Hg 2 CuTi-type inverse Heusler alloy structure and ferrimagnetic ground state. Our study reveals the half-metallic electronic structure with highly spin-polarized ∆ 1 band, which is robust against atomic disorder. Next we studied the electronic structure of Mn 2 RuAl/MgO and Mn 2 RuGe/MgO heterojunctions. We found that the MnAl-or MnGe-terminated interface is energetically more favorable compared to the MnRuterminated interface. Interfacial states appear at the Fermi level in the minority-spin gap for the Mn 2 RuGe/MgO junction. We discuss the origin of these interfacial states in terms of local environment around each constituent atom. On the other hand, in the Mn 2 RuAl/MgO junction, high spin polarization of bulk Mn 2 RuAl is preserved independent of its termination.

Exploring the Dynamics of Bound Water in Nylon Polymers with Terahertz Spectroscopy. ChemRxiv. Preprint. Terahertz (THz) spectroscopy was used to observe adsorbed water structure and dynamics within polymer films, ultimately providing a strong rationale for the observed rates of water desorption. The THz absorption spectra of nylon-6 films undergoes drastic changes during the hydration and drying process. Additionally, the structural change from g to a crystals, induced by the hydration, was observed by the characteristic band of a-nylon-6 at 6.5 THz. Importantly, the THz spectra of adsorbed water, as well as deuterated water, within in the nylon films were observed by the continuous measurement of a-nylon during dehydration. The differential spectra clearly show three absorption bands of water molecules named Peak I, II and III, which behaved differently between the H 2 O and D 2 O materials. The spectra were assigned using a combination of ab initio molecular dynamics simulations and solid-state density functional theory calculations, and were compared to previous spectral assignments of bulk water. The results show that the inclusion of H 2 O and D 2 O into polymer films results in a distinct set of spectral features that, while similar in frequencies to the dynamics of bulk water, represent significantly different motions owing to the unique chemical environment within the material. These results highlight the significant utility of using THz spectroscopy to study the hydration dynamics and spectral signature of bound water in this important class of materials. File list (4) download file view on ChemRxiv 20191018_Nylon_final.docx (1.02 MiB) download file view on ChemRxiv Peak3.gif (16.32 MiB) download file view on ChemRxiv Peak2.gif (16.78 MiB) download file view on ChemRxiv Peak1.gif (18.27 MiB)

An analog multiplier with a hybrid structure where crystalline oxide semiconductor (OS), specifically c-axis-aligned crystalline In-Ga-Zn oxide, based FETs (OS-FETs) are stacked on Si-FETs is fabricated. The analog multiplier demonstrates favorable multiplier characteristics such as high linearity, long data retention, and small device-to-device variation. An analog vector-by-matrix multiplier composed of the analog multiplier and an offset circuit formed of a programmable current source and a programmable current sink with the hybrid structure is proposed. The validity of the proposed analog vector-by-matrix multiplier is verified by employing it in a neural network trained to recognize handwritten digits. According to the circuit simulation results, the analog vector-by-matrix multiplier allows the network to achieve adequately high recognition accuracy, suggesting the suitability of the multiplier for running neural networks.

Antiferromagnet (AFM)/ferromagnet (FM) heterostructures with broken inversion symmetry are perceived to open new opportunities for nonvolatile spintronic devices. Previous studies of such systems have demonstrated an emergence of spin-orbit torques (SOTs) in the heterostructures which are strong enough to bring about magnetization reversal. The impact of broken inversion symmetry and spin-orbit coupling also leads to an emergence of the Dzyaloshinskii-Moriya interaction (DMI) which governs the magnetic configuration and magnetization reversal. In this work, we study the SOT-induced effective fields and DMI in a heterostructure with an antiferromagnetic PtMn layer and a ferromagnetic [Co/Ni] multilayer and compare the results with a reference Pt/[Co/Ni] system. Magnetotransport measurements reveal the same sign and similar magnitude of SOT-induced effective fields for the two systems while current-induced domain wall motion measurements under in-plane fields reveal the opposite sign and smaller magnitude of DMI at the PtMn/[Co/Ni] interface compared to the Pt/[Co/Ni]. The obtained results offer in-depth information concerning the manifestations of spin-orbit interactions in AFM/FM systems, which is key to understanding of static magnetic configuration and magnetization reversal for their possible applications in antiferromagnetic spintronics.