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Structural properties of rhombohedral α‐(AlxGa1−x)2O3 thin films grown by two combinatorial pulsed laser deposition (PLD) techniques are investigated for the entire composition range. One α‐(AlxGa1−x)2O3 thin film is deposited on a 2 inch in diameter large a‐plane sapphire substrate using the continuous composition spread (CCS) PLD technique to fabricate a thin film with varying Al content ranging between x = 0.13 and x = 0.84. Laterally homogeneous α‐(AlxGa1−x)2O3 thin films exhibiting discrete Al contents are fabricated using radially segmented PLD targets on (11.0) Al2O3. Independent of the PLD technique, for x ≈ 0.55, a change from relaxed to pseudomorphic growth is observed as confirmed by the evolution of in‐ and out‐of‐plane lattice constants. The crystal structure is studied depending on the cation composition by X‐ray diffraction confirming the fabrication of epitaxial, corundum‐structured thin films. [ABSTRACT FROM AUTHOR]

(AlxGa1−x)2O3 thin‐film layers in the metastable orthorhombic κ‐modification are deposited heteroepitaxially on unintentionally doped ZnO buffer layers on heavily Al‐doped and highly conductive ZnO back contact layers by pulsed laser deposition. The back contact layers potentially serve as electrodes for ferroelectric hysteresis measurements and improve the performance of device applications such as Schottky barrier diodes or quantum‐well infrared photodetectors (QWIPs). The alloy layers cover a broad composition range of 0 ≤ x ≤ 0.48 for which X‐ray diffraction (XRD) patterns confirm the same high crystal quality as for layers grown on single‐crystalline substrates. Epitaxial relations of the κ‐phase layers to the ZnO thin‐film templates are determined and both in‐ and out‐of‐plane lattice constants follow a linear evolution with Al content in agreement with Vegard's law. Smooth surface morphologies are verified in atomic force microscopy images. Finally, a 15‐layer‐pair κ‐(Al0.27Ga0.73)2O3/κ‐Ga2)O3 quantum‐well superlattice (SL) structure is similarly deposited on the ZnO:Al back contact layer and shows sharp SL fringes up to the fifth order in XRD measurements confirming excellent crystal quality and abrupt interfaces in the heterostructure. The results render ZnO:Al as a promising back contact layer for QWIP applications and the determination of electrical polarizations of κ‐phase alloy layers. [ABSTRACT FROM AUTHOR]

Herein, a ferrimagnetic manganese zinc ferrite (Mn0.5Zn0.5Fe2O4) film with a thickness of 200 nm is prepared without a buffer layer on strontium titanate (001) (SrTiO3) using pulsed laser deposition. Its magnetic properties are investigated using superconducting quantum interference device (SQUID), X‐ray absorption spectroscopy with subsequent X‐ray magnetic circular dichroism (XMCD) and magneto‐optic Kerr effect (MOKE). Hysteresis loops derived from SQUID exhibits bulk‐like properties. This can further be confirmed by bulk‐like XMCD spectra. In remanent magnetization, an in‐plane magnetization with basically no out‐of‐plane component is found. The magnetic moments derived by the sum rule formalism from the XMCD data are in good agreement to the magnetization observed by SQUID and MOKE. XMCD as well as MOKE reveal an in‐plane angular fourfold magnetic anisotropy with the easy direction along [110] for (Mn0.5Zn0.5)Fe2O4 on SrTiO3. The element‐specific magnetic moments from XMCD show a stronger contribution of Fe to the anisotropy than of Mn and distinct contributions of the orbital moments. [ABSTRACT FROM AUTHOR]

Herein, the magnetoelectric (ME) performance of epitaxial multilayer composite films built from nanometer‐thick layers of multiferroic BiFeO3 and ferroelectric BaTiO3 is reviewed. A successful implementation of shadow‐mask pulsed laser deposition considerably reduces the interface and surface roughness of the multilayers. In dependence of double‐layer thickness and the degree of structural perfection, the multilayers show high ME voltage coefficients up to 480 V cm−1 Oe−1 at 300 K and 0 T bias magnetic field. With decreasing double‐layer thickness, an interface‐driven effect critically enhances the ME coupling in this strain and charge–comediated system. Interestingly, the characteristics of temperature and DC magnetic field dependencies of magnetoelectric voltage coefficients change with the transition from the 2D to 3D character of the single layers, i.e., for BiFeO3 layers thicker than 5 nm within the multilayers. These changes are attributed to variations of the contributing ME coupling mechanisms. Furthermore, scanning transmission electron microscopy (STEM) with energy‐dispersive X‐ray (EDX) spectroscopy mapping‐based nanoanalysis indicates that chemical effects at the interfaces play an important role for the ME performance of the BiFeO3–BaTiO3 multilayer thin films. [ABSTRACT FROM AUTHOR]

, , , , and thin films were fabricated by pulsed laser deposition at high and low temperatures resulting in crystalline single-phase normal, inverse, as well as disordered spinel oxide thin films with smooth surface morphology. The dielectric function, determined by spectroscopic ellipsometry in a wide spectral range from 0.5 to 8.5 eV, is compared with the magneto-optical response of the dielectric tensor, investigated by magneto-optical Kerr effect spectroscopy in the spectral range from 1.7 to 5.5 eV with an applied magnetic field of 1.7 T. Crystal field, inter-valence, and inter-sublattice charge transfer transitions, and transitions from to metal cation 3d or 4s bands are identified in both the principal diagonal elements and the magneto-optically active off-diagonal elements of the dielectric tensor. Depending on the degree of cation disorder, resulting in local symmetry distortion, the magneto-optical response is found to be strongest for high crystal quality inverse spinels and for disordered normal spinel structure, contrary to the first principle studies of and . The results presented provide a basis for deeper understanding of light-matter interaction in this material system that is of vital importance for device-related phenomena and engineering. [ABSTRACT FROM AUTHOR]