Ultrathin films (Formula presented) of (Formula presented) on (Formula presented) exhibit properties quite different from the bulk. They become ferromagnetically ordered around 150 K but remain insulating, instead of showing the insulator-to-ferromagnetic metal transition which occurs in bulk material or thicker films at this Ca concentration. Electron microscopy shows that such films are perfectly crystalline but have a crystal structure, imposed by the lattice mismatch with the substrate, which is different from that of the bulk or thick films. An important feature is a Jahn-Teller-like distortion of the (Formula presented) octahedra which is not present in the bulk and appears to be the cause of the changed physical properties.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1999|