YBa₂Cu₃O_7-x/SrTiO₃//LaAlO₃ heterostructures obtained by injection MOCVD

Abstract

YBa2C~307.x /Ba,Sr ,-,Ti03 /LaA103 heterostructures can be used as a basis for devices with voltage control in microwave circuits.Ba,SrI-,Ti03 (x=O-O.I)(BST) thin films have been epitaxially grown on LaAlO3 substrates using injection MOCVD. The excellent crystalline quality of the obtained BST films can be proven by a FWHM of <0,2" for the rocking curve of the (002) BST reflection. An AFM study revealed flat surfaces, showing a surface roughness R, as low as Inm.YBa2Cu307.x/Ba,Srl.x TiO3//LaA1o3 heterostmctures were than optimised. The Y B~~C U~O , .~ (YBCO) layers obtained on Ba,Srl-,TiO3 films are epitaxial with a FWHM of 0.45" for the (005) YBCO rocking curve and display very promising superconducting properties of T,=92K.Finally the microwave properties of the superconducting films were studied. For YBa2Cu307.x layers directly deposited on LaA103, surface resistance values of 0 , 3 2 M were obtained, while for YBa2Cu307.x /SrTi03//LaAI03 heterostructures, higher values of ImR at 8.5GHz were measured.

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

“…LaAlO 3 offers good lattice matching with many other perovskites, and is a good substrate for ferroelectric and/or superconducting thin films. − For this application, strontium titanate (SrTiO 3 ) is an excellent buffer material that provides a template layer for growing the superconducting film . In spite of a lattice mismatch of 3%, the growth of SrTiO 3 on LaAlO 3 (or vice versa) is characterized by an epitaxial cube-on-cube orientation. , Furthermore, the combination of LaAlO 3 with SrTiO 3 in itself is of great interest due to the formation of a high-density, 2D conducting electron gas at the interface, although both perovskites on their own are insulating, nonmagnetic oxides . The magnetic properties and the 2D superconductivity of the LaAlO 3 /SrTiO 3 system are the subject of ongoing investigations. − The rare coexistence of ferromagnetism and superconductivity is of particular interest .…”

“…267 In spite of a lattice mismatch of 3%, 266 the growth of SrTiO 3 on LaAlO 3 (or vice versa) is characterized by an epitaxial cube-on-cube orientation. 266,267 Furthermore, the combination of LaAlO 3 with SrTiO 3 in itself is of great interest due to the formation of a high-density, 2D conducting electron gas at the interface, although both perovskites on their own are insulating, nonmagnetic oxides. 268 The magnetic properties and the 2D superconductivity of the LaAlO 3 / SrTiO 3 system are the subject of ongoing investigations.…”