chapter  7
24 Pages

THIN FILM AND NANOSTRUCTURED MULTIFERROIC MATERIALS

ByB. Raneesh, Nandakumar Kalarikkal

The novel and exciting field of multiferroics has recently attracted a great deal of interest and promising results have already been reported. The term multiferroic was first used by H. Schmid in 1994. Crystals can be defined as multiferroic (MF) when two or more of the primary ferroic properties are united in the same phase (Schmid et. al., 1994). These days’ people have extended the meaning to incorporate some other long range orders, for example antiferromagnetic. Thus, multiferroic materials can been associated under the title magnetoelectric (ME) which was invented in 1960’s. The ME effect, meaning magnetic (electric) induction of polarization P (magnetization M), was first theoretically confirmed in 1959 (Dzyaloshinsky et. al., 1959) and Asrov et. al., confirmed this prediction experimentally in 1960 (Astrov et. al., 1960). During last 10 years, a broad class associated with magnet insulator came into existence recognized as the multiferroic. This new class of materials offers coexistence of long range order associated with magnetism as well as ferroelectricity, using the feasible effects of ferroelectric (FE) behavior through the adjusting associated with magnet field. Multiferroics with combined ferroic properties can apply to specific device applications such as multiple state memory elements, spintronics, and sensors (Martin et. al., 2008). The actual ME coupling among magnetism as well as electric orders in these multiferroics, provides an opportunity to magnetic polarization by making use of electrical field as well as the other way round. This has paved way for the manufacturing of new kind of memory devices, such as electric-field controlled magnetic random access memory (MERAM), in which data can be written electrically and read magnetically.