Magnetic and electrical properties of multiferroic BiFeO3, its synthesis and applications

Structure and local polar domains of Dy-modified BiFeO3–PbTiO3 multiferroic solid solutions

“…However, there are still some serious obstacles that need to be overcome before the potential practical applications of BFO in highly promising magnetoelectric memory devices, spintronic devices, etc., could be realized. 1,4,5 First, the synthesis of a pure BFO bulk material is difficult due to the unstable nature of the perovskite phase above 948 K during the solid state reaction and sintering process. Second, the large leakage current due to the existence of the mixed-valence Fe 2+ /Fe 3+ ions and oxygen vacancies makes it difficult, if not impossible, to display the intrinsic excellent ferroelectric properties.…”

“…Many chemically modified BiFeO 3 -based bulk materials were reported with enhanced ferroelectric and/or ferromagnetic properties. 5,[7][8][9][10][11][12][13][14][15] Among these materials, the solid solution of (1 À x)BiFeO 3 -xPbTiO 3 (BF-PT) has been proved to be of particular interest as it can be formed in a stable perovskite phase by the solid state reaction and exhibits a morphotropic phase boundary (MPB) approximately at x = 0.3. [15][16][17][18] In our previous work, [19][20][21] the magnetic ion Dy 3+ has been introduced into the BF-PT system to form a (1 À x)[0.9BiFeO 3 -0.1DyFeO 3 ]-xPbTiO 3 (BDF-xPT) pseudo-binary solid solution in order to further improve the multiferroic properties.…”

Application of BiFeO3 and Bi4Ti3O12 in ferroelectric memory, phase shifters of a phased array, and microwave HEMTs

“…In contrast, a BiFeO 3 sub strate should have high conductivity (due to, e.g., dop ing with Ca [41]). A review by Skorikov et al [63] considers in detail possible A and B site substitutions in BiFeO 3 with the aim of optimizing its properties for particular applica tions. In this approach, because of the film homogene ity and absence of diffusion, there is possibly no need in a buffer layer.…”

Piezoresponse and magnetic properties of multiferroic (1−x)Bi0.9Dy0.1FeO3–xPbTiO3 solid solution

“…Various forms of BiFeO 3 , including thin films, nanostructures, and chemically modified BiFeO 3 -based bulk materials were reported with enhanced ferroelectric properties. 6 Meanwhile, the ferromagnetism was improved by doping with a wide range of different ions, such as A-site substitutions with Ba 2þ , Pb 2þ , Ca 2þ , Dy 3þ , La 3þ , and Tb 3þ , B-site substitution with Co 2þ , and A-site and B-site co-substitutions with Pr 3þ and Mn 2þ , and by forming solid solutions with other perovskites including PbTiO 3 and BaTiO 3 . 6,[8][9][10][11][12][13] It is believed that the addition of certain ions into the BiFeO 3 crystal structure can disrupt the spiral spin modulation, transforming the antiferromagnetic phase into a (weakly) ferromagnetic (FM) state, thereby enhancing the ferromagnetic property.…”

“…1,5 These outstanding properties entitle BiFeO 3 a fascinating room-temperature multiferroic material which could be potentially useful in such applications as magnetoelectric memories, spintronic devices, microwave resonators, and filters. 5,6 However, there are some serious obstacles which need to be overcome before practical applications could be realized. First, difficulties have been encountered in the fabrication of high-quality phase-pure BiFeO 3 bulk materials because of the evaporation of bismuth oxide and the unstable perovskite phase above 675 C. Second, the large leakage current due to the existence of the mixed valence Fe 2þ /Fe 3þ ions and oxygen vacancies, especially in bulk materials sintered by conventional solid state reaction process, makes it difficult, if not impossible, to display the widely expected outstanding ferroelectric properties.…”