Yttrium Iron Garnet/Barium Titanate Multiferroic Composites

Abstract

Dense multiferroic 0‐3 type composites encompassing BaTiO3 and Y3Fe5O12 were fabricated by the solid‐state reaction method. X‐ray diffraction data combined with scanning electron microscopy imaging show virtual immiscibility between the two phases, with the Y3Fe5O12 ferrimagnetic phase well dispersed in the tetragonal BaTiO3 ferroelectric matrix. Raman spectroscopy analyses corroborate the polar nature of the BaTiO3 matrix in composites with a Y3Fe5O12 content as great as 40 wt%. Ferrimagnetism is detected in all composites and no additional magnetic phases are distinguished. Although these dense ceramics can be electrically poled, they exhibit a very weak magnetoelectric response, which slightly increases with Y3Fe5O12 content.

Electric-field control of spin-wave power flow and caustics in thin magnetic films

“…2 effects note that in the case of good quality magnetic film on a substrate, e.g., YIG on a gadolinium gallium garnet, the applied electric field can be quite large. In fact, we take into account already existing experimental [4,21,22] and theoretical reports [23] where an electric field of such magnitude is also discussed.…”

Enhanced piezomagnetic coefficient of cobalt ferrite ceramics by Ga and Mn doping for magnetoelectric applications

“…Magnetic metallic alloys or spinel oxides are used for the former component, while ferroelectric polymers or perovskite phases are preferred for the latter one. 2,[4][5][6][7][8] Interest in cofired ceramic composites has grown due to their low cost, easy manufacturing, possibility of co-sintering the magnetostrictive and piezoelectric oxide phases, and high electrical resistivity when compared to metallic alloys as Metglas or Terfenol-D. [9][10][11][12][13][14] Among magnetostrictive phases, CoF e 2 O 4 (CFO) stands out because of its very high magnetostriction (λ). 15 However, studies in ME composites formed by CFO-based compositions mostly resulted in ME coefficients lower than those using N iF e 2 O 4 -based magnetostrictive phases.…”

“…15 However, studies in ME composites formed by CFO-based compositions mostly resulted in ME coefficients lower than those using N iF e 2 O 4 -based magnetostrictive phases. 9,13,[16][17][18] This is so because the magnetoelectric coupling in composites results from changes of polarization in the piezoelectric phase caused by the dynamical mechanical deformation of the magnetostrictive one under a varying magnetic field. Thus, the relevant characteristic to obtain high ME coupling is a large strain sensitivity dλ dH (or effective piezomagnetic coefficient), and CFO shows low piezomagnetic coefficient because its high magneto-crystalline anisotropy and coercive field.…”

Applications of Multiferroics

“…To be useful in advanced applications, multiferroic materials must have extremely high magnetoelectric coupling strength at and above 300 K. The electrical requirements of molecules to show ferroelectric and ferromagnetic ordering are opposed, which explains the paucity of single-phase multiferroic materials. For example, conventional ferroelectric materials like BaTiO 3 require an empty d-orbital of Ti, while unpaired electrons are necessary to display magnetism [7,8]. In addition, symmetry criteria are a consideration and thus, only 13-point groups are capable of demonstrating the multiferroic characteristic.…”