Orientation dependence of magnetoelectric coefficient in BaTiO3/CoFe2O4

Abstract

Using the three-dimensional space coordinate transformation approach, orientation dependence of the longitudinal magnetoelectric coefficient αE33 in tetragonal BaTiO3/face centered cubic (fcc) CoFe2O4 composites was calculated in arbitrary directions. A clamp-free condition is used in the calculation. The direction along which αE33 is maximum is a function of psij, pεij, dij of piezoelectric phase and msij, mμij, qij of magnetostrictive phase referred to the crystallographic coordinate system. For a fixed CoFe2O4 orientation, the maximum αE33 lies along [001] axis of BaTiO3. And for a fixed BaTiO3 orientation, the maximum αE33 lies along [001] axis and a large αE33 also lies along [11l] (l > 0) of CoFe2O4. BaTiO3 || [001]/CoFe2O4 || [001] combination has the maximum αE33 which is 641 mV/cm Oe. The maximum αE33 is about 2 times of that of random orientated materials. Volume fraction is quite independent of orientation changes of both piezoelectric and magnetostrictive phases and the volume fraction for magnetostrictive phase f around 0.76 obtains the largest αE33. Our results suggest an approach of significantly enhancing magnetoelectric coefficient of composite multiferroic materials through crystal orientation and texture engineering.

3D BaTiO3 Flower Based Polymer Composites Exhibiting Excellent Piezoelectric Energy Harvesting Properties

“…BT is a high piezoelectric material with intrinsic dipoles in the BT lattice. [ 34,35 ] The piezoelectric mechanism of BT can be understood that intrinsic dipoles in BT are aligned upon poling and stretched/squeezed upon compression/the reversed force to the BT lattice). [ 34,35 ] The decrease at f BTF ≈ 15–25% may be due to a deteriorated film structure at high filler loadings.…”

“…[ 34,35 ] The piezoelectric mechanism of BT can be understood that intrinsic dipoles in BT are aligned upon poling and stretched/squeezed upon compression/the reversed force to the BT lattice). [ 34,35 ] The decrease at f BTF ≈ 15–25% may be due to a deteriorated film structure at high filler loadings. As shown in Figure S3 (Supporting Information), pores increase in the composites with filler loading at high BTFs loadings, which may result in decreased performances of the PENG.…”

Preferentially Oriented Nanometer-Sized CoFe2O4 Mesocrystals Embedded in the BiFeO3 Matrix for Opto-Magnetic Device Applications

“…This is similar to that reported for the BTO−CFO system, wherein it was suggested that the shape anisotropy of the tetragonal-structured BTO is essential for giving rise to the crystalline orientation dependence of the magnetoelectric coupling observed in the bilayer BTO−CFO system. 61 It is apparent that controllability of the crystal shape anisotropy and orientation of CFO mesocrystals can provide additional handles for manipulating the magnetic properties, which is important for practical applications such as bitpatterned media wherein the magnetic anisotropy of CFO mesocrystal served as a medium to store bit information. 17 Thus, we believe that our findings can pave an alternative avenue for investigating the largely unexplored feasibility assessments in utilizing the engineered CFO mesocrystals for bit-patterned media applications.…”

Orientation Dependence of Elastic and Piezoelectric Properties in Rhombohedral BiFeO3

“…Matrices of elastic stiffnesses c ij and piezoelectric constants d ij are presented in [6 × 6] and [3 × 6] rank tensors, respectively. According to Euler’s rotation laws, physical quantity matrices in a new orientation are obtained by two-step product operations with transformation matrices A , N , and M [21,22].…”