Tham khảo tài liệu 'ferroelectrics material aspects part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 21 Amino-Acid Ferroelectric Thin Films Balashova . and Krichevtsov . Ioffe Physico-technical Institute of RAS St-Petersburg Russia 1. Introduction The family of amino-acid ferroelectrics involves large number of crystals the chemical composition of which is based on combinations of different amino-acids betaine Ch3 3N CH2COO- sarcosine CH3NHCH2COOH glycine H2NCH2COOH and non-organic acids H3PO3 H3AsO4 H3PO4 HCl H2SO4 or salts. The most well known example of amino-acid ferroelectrics - triglycine sulphate TGS - was discovered in 1956 Matthias et al. 1956 . After that the amino-acid ferroelectric crystals were synthesized on basis of sarcosine and in 80-th of the last century on basis of betaine amino-acids Albers et al. 1988 . The interest to betaine amino-acid ferroelectrics is concerned with large variety of phases ferroelectric ferroelastic antiferroelectric antiferrodistortive incommensurate glasslike state and so on phase transformations and with ferroelectric properties observed in these crystals. For example a record value of dielectric constant at the ferroelectric phase transition g 106 has been observed in betaine arsenate crystals. Experimental and theoretical investigations of amino-acid ferroelectric single crystals has been carried out in large number of works and main results of these studies were summarized in review papers Albers 1988 Schaack 1990 . Recently it was found Balashova et al. 2008 2011a that thin films of betaine phosphite BPI and deuterated betaine phosphite DBPI can be manufactured by evaporation method on different substrates. The BPI films consist of large single-crystalline blocks and show ferroelectric properties mainly analogous to the bulk BPI crystals. The differences in dielectric behavior of films and bulk samples are related to film-substrate interaction and specifics of domain structure. At present large attention is paid to ferroelectric thin films because of their potential applications in information storage systems
