R. Todorovska

Thermal decomposition of yttrium–iron citrates prepared in ethylene glycol medium

Thermal decomposition of yttrium–iron citric complexes, prepared in ethylene glycol medium, with mole ratio Y/Fe=1 or 3:5 (intermediates in the production of YFeO3 and Y3Fe5O12 by the polymerized complex method) is studied. A scheme of the thermally induced processes is proposed.

Spray pyrolysis deposition of α-Fe2O3 thin films using iron (III) citric complexes

Thin films of α-Fe2O3 have been deposited on fused silica substrates (heated at 500 °C) by an in situ spray pyrolysis method using ethylene glycol solution of Fe(III)-citric complexes and O2 as a carrier gas. The monophase composition of the films was confirmed by the X-ray diffractometry. Their morphology and roughness have been estimated by means of atomic force microscopy (AFM).

Highly Crystalline Y3Fe5O12 Thin Films by Cictric Spray Pyrolysis

Ethylene glycol solution of mixed-metal Y(III)-Fe(III) citric complexes has been used as a starting material for a spray pyrolysis deposition of Y3Fe5O12 (YIG) thin films on silica and on single crystal Y3Al5O12 (YAG) substrates heated up to 500°C. O2 was used as a carrier gas. A post-deposition thermal annealing at 800–1100°C was applied. Films of 0.1–1.2 μm in thickness were obtained. Their composition, binding energies, crystal structure, morphology, and magnetic properties were studied. Phase homogeneous polycrystalline or highly textured YIG films were obtained on silica or YAG substrates at annealing temperatures of 860° and 960°C, respectively. The crystallite grain sizes of both type of layers were ∼80 nm along the (400) plane. A columnar structure of the films with the column diameter of 400–500 nm might be supposed following the atomic force microscopy data. Saturation and permanent magnetizations along the easy axis of 1545 Gs and 816 Gs, respectively, and coercive force along the same axis of 4 Oe were measured.

Preparation of YBCO superconducting films by spray deposition and MTG processing

Abstract Superconducting YBCO films ( T c = 88 K , J c = 4200 A / cm 2 (77 K , 0 T )) were prepared using spray deposition and melttextured growth (MTG) processing. The influence of different substrates and the metal atom ratio Y:Ba:Cu in the initial solutions on the structure and properties of the films obtained was studied.

In Situ Deposition of HTSC YBCO Thin Films by High Temperature Spray Pyrolysis

The spray pyrolysis (deposition from aerosol) is an approved perspective low cost (simple) non-vacuum method for preparation of HTSC films. By “in situ” spray pyrolysis (without postannealing) more smooth HTSC films can be obtained at considerably lower synthesis temperatures as compared to the low temperature spray pyrolysis (with postannealing); at the same time a wider range of substrates can be used due to the minimum surface-film interface width [1, 2]. An additional advantage of the method is the possibility of depositing HTSC thin films on large-area surfaces.