ABSTRACT
Contents 4.1 Introduction................................................................................................. 100 4.2 Examples of Magnatic Multiferroics ........................................................ 101
4.2.1 Manganites ..................................................................................... 101 4.2.1.1 TbMnO3 and DyMnO3 ................................................. 101 4.2.1.2 Orthorhombic HoMnO3 and YMnO3 ........................ 101 4.2.1.3 A-Site Doping Eect in RMnO3 .................................. 105 4.2.1.4 RMn2O5 ........................................................................... 106
4.2.2 Other Type-II Multiferroics ......................................................... 107 4.2.2.1 Ca3CoMnO6.................................................................... 108 4.2.2.2 Organic Magnetic Multiferroics ................................. 108
4.3 Mechanisms of Spin Order-Induced Ferroelectricity .......................... 110 4.3.1 Symmetry Consideration ............................................................. 110
4.3.1.1 Chiral Structure ............................................................. 110 4.3.1.2 Parity Structure ............................................................. 112 4.3.1.3 Other Possibilities ......................................................... 113
4.1 Introduction In this chapter, type-II multiferroics are discussed [1-3]. ey are o en referred to as magnetic ferroelectrics or magnetic multiferroics, in which the ferroelectricity is directly generated by some type of frustrated spin order. Khomskii [4] viewed these materials as the most exciting development in the eld of multiferroics.
