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FeMn/Co thin-films, a purely metallic exchange-bias system, were prepared on (100)-oriented MgO single crystals. The layers were grown by molecular beam epitaxy (MBE). The crystalline and magnetic properties could be tuned by using sputtered Pt buffer layers deposited at variable temperatures. A transition of the crystalline orientation from (111)-terminated layers at lower deposition temperatures to (100)-terminated layers at temperatures higher than 950 K was established and the impact on the magnetic sample properties was investigated. Here, the detailed sample preparation process is shown together with low energy electron diffraction (LEED), medium energy electron diffraction (MEED), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements revealing the samples structure and composition. The crystalline orientation of Pt was imprinted to the magnetic layer stack and clearly influenced the exchange-bias (EB) and coercive field ( HC) as shown by superconducting quantum interference device (SQUID) and magneto-optical Kerr effect (MOKE) measurements. Furthermore, a correlation between the crystallite size and the temperature dependent magnetic properties could be identified. [ABSTRACT FROM AUTHOR]

Abstract: The effect of anisotropic strain induced by SrTiO3 (STO) substrate with different orientations on charge ordering (CO) behavior in epitaxial Sm0.5Ca0.5MnO3 (SCMO) films was investigated using cross-sectional transmission electron microscopy at 103K. Incommensurate modulated structure caused by CO transition was observed in the SCMO film grown on a [101]-oriented STO substrate while none were found for SCMO film grown on a [100]-oriented STO substrate. This distinctive orientation-dependent CO transition is correlated with anisotropic strain in the films induced by lattice mismatch, confirming the previous results for growth on different substrates. [Copyright &y& Elsevier]

Abstract: FePd and CoPd alloy thin films were prepared on MgO single-crystal substrates of (001) B1, (110) B1, and (111) B1 orientations at 600°C by ultra high vacuum rf magnetron sputtering. L10-FePd(001) films with the c-axis perpendicular to the substrate surface are obtained on MgO(001) B1 substrates. FePd epitaxial films consisting of L10(110) and L10(011) crystals are formed on MgO(110) B1 substrates. The c-axis of L10(110) crystal is parallel to the substrate surface, whereas that of L10(011) crystal is 44° canted from perpendicular direction. L10-FePd(111) films with the c-axis 54° canted from the perpendicular direction are formed on MgO(111) B1 substrates. L10 ordering degree of these FePd films varies depending on the substrate orientation. On the other hand, disordered CoPd thin films of (001) A1, (110) A1, and (111) A1 orientations epitaxially grow on MgO substrates of (001) B1, (110) B1, and (111) B1 orientations, respectively. The magnetization properties of L10 ordered FePd and A1 disordered CoPd thin films are influenced by the crystal structure, the ordering degree, and the film orientation. [Copyright &y& Elsevier]

We demonstrate superconducting qubits using epitaxially grown Josephson junctions. A fully epitaxial NbN/AlN/NbN trilayer on MgO (100) substrate is processed by photolithography and dry-etching into transmon qubits with a large Josephson energy. The tunnel barrier made of cubic-phase AlN, rather than the ordinary hexagonal phase, is the key to avoid piezoelectric coupling to the phonon bath. The energy-relaxation time and the spin-echo decay time of ∼500 ns are observed in the qubits that are coupled to a monolithically made coplanar waveguide resonator. [ABSTRACT FROM AUTHOR]

V0.6W0.4N alloys are grown on MgO(001) by ultrahigh vacuum reactive magnetron sputtering from V and W targets in 10 mTorr pure-N2 atmospheres at temperatures Ts ranging from 600 to 900 °C. Based on x-ray diffraction and transmission electron microscopy results, all films have the B1-NaCl crystal structure and grow with a cube-on-cube epitaxial relationship to the substrate, (001)VWN|(001)MgO and [100]VWN|[100]MgO. Rutherford backscattering spectrometry analyses show that the N content in V0.6W0.4Nx alloys decreases with increasing Ts from overstoichiometric with x = 1.13 at 600 °C, to approximately stoichiometric with x = 1.08 at 700 °C, to understoichiometric at 800 °C (x = 0.80) and 900 °C (x = 0.75). High-resolution scanning transmission electron microscopy, Z-contrast, and selected-area electron diffraction investigations of V0.6W0.4N(001) alloys grown at 600 and 700 °C reveal the onset of W ordering on adjacent 111 planes of the metal sublattice; no ordering is observed for understoichiometric films grown at higher temperatures. [ABSTRACT FROM AUTHOR]