Abstract: Apparatus and methods for growing films of complex layered metal oxides with high stoichiometries and high crystal qualities are provided. The layered complex metal oxides include two or more metals and oxygen and have a layered structure. The methods, which are referred to as hybrid pulsed laser deposition (hybrid PLD), synergistically combine the advantages of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) to grow complex metal oxide films that include metals with very different vapor pressures.

Abstract: High-quality membranes of complex oxide and complex nitrides are provided. Also provided are method of making the membranes by releasing films of the complex oxides and nitrides from an epitaxial heterostructure using metal islands on the surface of the films as strain-absorbing supports. The methods facilitate the release of flat, large-area membranes characterized by the absence of, or a very low density of, cracks and/or wrinkles. The released membranes are free of the surface organic residues that are present on membranes released with the aid of a polymer support.

Abstract: A structure includes a semiconductor substrate. The structure further includes a first oxide structure disposed above the semiconductor substrate and a second oxide structure disposed above the first oxide structure and configured to form a conductive path at an interface between the first oxide structure and the second oxide structure. The structure additionally includes a conducting structure extending from the interface through the second oxide structure. The conducting structure is configured such that in response to a voltage being applied to the conducting structure, a charge carrier is generated below the second oxide structure along the conductive path.

Abstract: Optoelectronic transducers that convert a femtosecond (fs)-timescale laser pulse into an a.c. electrical current pulse with an extremely high frequency and a high quality factor (Q) are provided. Both the frequency and amplitude of the a.c. electrical current pulse can be dynamically tuned by the application of a varying bias magnetic field. The optoelectronic transducers are based on a trilayered freestanding membrane that functions as both an acoustic cavity and a magnon cavity. The freestanding membrane includes an electrical conductor layer, a magnetic insulator layer, and a dielectric layer arranged in a vertical stack.

Abstract: Apparatus and methods for growing films of complex layered metal oxides with high stoichiometries and high crystal qualities are provided. The layered complex metal oxides include two or more metals and oxygen and have a layered structure. The methods, which are referred to as hybrid pulsed laser deposition (hybrid PLD), synergistically combine the advantages of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) to grow complex metal oxide films that include metals with very different vapor pressures.

Abstract: Optoelectronic transducers that convert a femtosecond (fs)-timescale laser pulse into an a.c. electrical current pulse with an extremely high frequency and a high quality factor (Q) are provided. Both the frequency and amplitude of the a.c. electrical current pulse can be dynamically tuned by the application of a varying bias magnetic field. The optoelectronic transducers are based on a trilayered freestanding membrane that functions as both an acoustic cavity and a magnon cavity. The freestanding membrane includes an electrical conductor layer, a magnetic insulator layer, and a dielectric layer arranged in a vertical stack.

Abstract: Voltage-controlled spin field effect transistors (“spin transistors”) and methods for their use in switching applications are provided. In the spin transistors, spin current is transported from a spin injection contact to a spin detection contact through a multiferroic antiferromagnetic channel via magnon propagation. The spin current transport is modulated by the application of a gate voltage that increases the number of domain boundaries the multiferroic antiferromagnetic material.

Abstract: Apparatus and methods for growing films of complex layered metal oxides with high stoichiometries and high crystal qualities are provided. The layered complex metal oxides include two or more metals and oxygen and have a layered structure. The methods, which are referred to as hybrid pulsed laser deposition (hybrid PLD), synergistically combine the advantages of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) to grow complex metal oxide films that include metals with very different vapor pressures.

Abstract: Aluminum oxide (Al2O3) thin films having a high ?-phase purity and low defect density and methods for making the aluminum oxide thin films are provided. Also provided are epitaxial heterostructures that incorporate the aluminum oxide thin films as growth substrates and methods of forming the heterostructures. The Al2O3 films are pure, or nearly pure, ?-Al2O3. As such, the films contain no, or only a very low concentration of, other Al2O3 polymorph phases. In particular, the Al2O3 films contain no, or only a very low concentration of, the ?-Al2O3 polymorph phase.

Abstract: Methods and systems for forming complex oxide films are provided. Also provided are complex oxide films and heterostructures made using the methods and electronic devices incorporating the complex oxide films and heterostructures. In the methods pulsed laser deposition is conducted in an atmosphere containing a metal-organic precursor to form highly stoichiometric complex oxides.

Abstract: Aluminum oxide (Al2O3) thin films having a high ?-phase purity and low defect density and methods for making the aluminum oxide thin films are provided. Also provided are epitaxial heterostructures that incorporate the aluminum oxide thin films as growth substrates and methods of forming the heterostructures. The Al2O3 films are pure, or nearly pure, ?-Al2O3. As such, the films contain no, or only a very low concentration of, other Al2O3 polymorph phases. In particular, the Al2O3 films contain no, or only a very low concentration of, the ?-Al2O3 polymorph phase.

Abstract: Methods and systems for forming complex oxide films are provided. Also provided are complex oxide films and heterostructures made using the methods and electronic devices incorporating the complex oxide films and heterostructures. In the methods pulsed laser deposition is conducted in an atmosphere containing a metal-organic precursor to form highly stoichiometric complex oxides.

Abstract: Methods and systems for forming complex oxide films are provided. Also provided are complex oxide films and heterostructures made using the methods and electronic devices incorporating the complex oxide films and heterostructures. In the methods pulsed laser deposition is conducted in an atmosphere containing a metal-organic precursor to form highly stoichiometric complex oxides.

Abstract: Heterostructures that include a bilayer composed of epitaxial layers of vanadium dioxide having different rutile-to-monoclinic phase transition temperatures are provided. Also provided are electrical switches that incorporate the heterostructures. The bilayers are characterized in that they undergo a single-step, collective, metal-insulator transition at an electronic transition temperature. At temperatures below the electronic transition temperature, the layer of vanadium dioxide having the higher rutile-to-monoclinic phase transition temperature has an insulating monoclinic crystalline phase, which is converted to a metallic monoclinic crystalline phase at temperatures above the electronic transition temperature.

Abstract: Magnetoelectric devices based on piezoelectric/magnetostrictive bilayers are provided. Also provided are methods of using the devices to modulate or to sense the magnetization of the magnetostrictive material. The devices include an island of magnetostrictive material that is strain-coupled to a thin layer of a piezoelectric material at an interface. A bottom electrode is placed in electrical communication with one surface of the piezoelectric film, and an unpaired top electrode is placed in electrical communication with a second, opposing surface of the piezoelectric film.

Abstract: Voltage-controlled spin field effect transistors (“spin transistors”) and methods for their use in switching applications are provided. In the spin transistors, spin current is transported from a spin injection contact to a spin detection contact through a multiferroic antiferromagnetic channel via magnon propagation. The spin current transport is modulated by the application of a gate voltage that increases the number of domain boundaries the multiferroic antiferromagnetic material.

Abstract: Magnetoelectric heterostructures, and related articles, systems, and methods, are generally described.

Abstract: Methods and systems for forming complex oxide films are provided. Also provided are complex oxide films and heterostructures made using the methods and electronic devices incorporating the complex oxide films and heterostructures. In the methods pulsed laser deposition is conducted in an atmosphere containing a metal-organic precursor to form highly stoichiometric complex oxides.

Abstract: Magnetoelectric devices based on piezoelectric/magnetostrictive bilayers are provided. Also provided are methods of using the devices to modulate or to sense the magnetization of the magnetostrictive material. The devices include an island of magnetostrictive material that is strain-coupled to a thin layer of a piezoelectric material at an interface. A bottom electrode is placed in electrical communication with one surface of the piezoelectric film, and an unpaired top electrode is placed in electrical communication with a second, opposing surface of the piezoelectric film.

Abstract: Spintronic devices based on metallic antiferromagnets having a non-collinear spin structure are provided. Also provided are methods for operating the devices. The spintronic devices are based on a bilayer structure that includes a spin torque layer of an antiferromagnetic material having a non-collinear triangular spin structure adjoining a layer of ferromagnetic material.