Papers by Author: Ludwig Schultz

Abstract: Recovery, recrystallisation and grain growth processes as well as the formation of a solid solution and the phase separation of a homogeneous material into a heterogeneous one are observed for Cu-Ag-Zr alloys heat-treated at different temperatures by means of mechanical, electrical and microstructural analyses. Heat treatments are shown to be an effective tool to enhance the strain to failure. If applied between several deformation steps the heat treatment causes an increase of both strain and strength limits.

Abstract: Textured polycrystalline NiMnGa alloys were prepared by directional solidification. Alloys were chosen to have either the 7M or the 5M modulated martensitic structure after proper heat treatment. Mechanical training allowed to reduce the twin boundary pinning stress to below the magnetically induced stress. Thus, magnetic field induced changes in the mechanical behaviour could be demonstrated. The conditions of preparation and mechanical training will be discussed together with their influence on structure, microstructure, and the magneto-mechanical behaviour.

Abstract: Hard magnetic Sm-Co thin films were prepared on Cr buffered MgO(001) single crystals by pulsed laser deposition. The texture of the films as well as the magnetic properties were measured for films deposited at different temperatures. Sm-Co is a system with high uniaxial magnetic anisotropy, where the c-axis is the axis of easy magnetization. Thin films of this material, with high coercivity and remanence, are of increasing interest for application in magnetic miniature devices. To explore the potential of this permanent magnetic material, a strong texture with a wellaligned c-axis is required. Analysis of several pole figures shows that mainly two types of orientations develop which grow epitaxially on Cr. For one orientation, the c-axis lies n the sample surface parallel to Cr(110). The c-axis of the second orientiation is tilted by 60° out of the surface plane.