We investigate the influence of a well-defined reversible biaxial strain ≤ 0.12 % on the magnetization ( M ) of epitaxial ferromagnetic manganite films. M has been recorded depending on temperature, strain and magnetic field in 20 -50 nm thick films. This is

No abstract

No abstract

The effective properties of piezoelectric laminates have been analyzed, based on the calculation of internal fields and making use of a simple matrix manipulation method. The results are expressed in a compact notation which is convenient for numerical implementation and at the same time suitable for further analytical treatments. A detailed analysis of fully compatible ferroelectric domain structures shows, that the results for arbitrary piezoelectric laminates can be further simplified and specific property relationships for rank-1 laminates of tetragonal and rhombohedral crystals are derived. The method is finally applied to the analysis of various hierarchical domain structures. Detailed orientation relationships between the particular domains in some important domain pattern are given to make these structures accessible for the presented method. Some numerical results for tetragonal barium titanate illustrate the effects of different domain arrangements on the effective properties.

We are concerned with the calculation of macroscopic linear thermo-electro-elastic properties for polycrystalline and composite materials. Due to the complexity of the coupled electro-mechanical field equations in 3D, in most cases exact solutions are impossible.Therefore we apply the well-known Effective field and Effective medium approximation. This can now be done since recently explicit results for the fully coupled Eshelby tensors became available. We present shortly the basics of the theory and illustrate it by numerical evaluations. The resulting effective material constants of piezoelectric ceramics depend non-monotonously on the degree of poling, and the properties of composites may strongly differ from predictions on the basis of simple rule of mixtures.