Condensed Matter Physics Seminar
Physical properties of perovskite metal-oxide thin films
Materials Physics and Applications Division
Los Alamos National Laboratory
The perovskite structure is a versatile structure. With skilled chemical manipulation, it can produce an incredibly wide array of phases with totally different functions such as ferroelectricity, magnetoresistance, conductivity, etc.
Epitaxial films of perovskite ferroelectric (FE) and ferromagnetic (FM) films such as Ba1-xSrxTiO3 (BST) and La1-xSrxMnO3 (LSM), respectively were grown by solution techniques. Solution chemistry, substrate, transformation pathway, and thermal processing conditions, all can have significant effects on thin film microstructure, orientation, and properties. For the tunable microwave devices, BST is an attractive candidate due to its tunable properties. A novel approach was used to reduce the losses in the BST thin films for their applications in tunable microwave devices. The BST films showed good tunable properties with low losses. A figure of merit as high as 87deg/dB at 16 GHz was achieved in the case of composite film of BST with low-loss MgO. The LSM films showed intrinsic magnetoresistance properties equivalent to the epitaxial films grown by physical vapor deposition techniques. High magnetoresistance values were achieved near room temperature by making multilayer coated films. The results demonstrate that solution techniques are alternative approaches to prepare high quality films of multifunctional materials.
Thursday, September 27, 2007
Gant Science Complex
Materials Science Building
(The seminar is followed by coffee/tea, cookies, and an informal discussions.)