Geometry and Electrical Properties of Grain Boundaries in Manganese Zinc Ferrite Ceramics

Abstract

For large‐grained manganese zinc (MnZn) ferrite ceramics, grain misorientation determined by electron backscatter diffractions and grain‐boundary resistance measured using microcontact impedance spectroscopy have been correlated. The degree of oxidation of grain boundaries and, hence, the barrier height depends on the overall grain‐boundary network as well as on the individual boundary structure; therefore, a statistical analysis has been performed based on several hundreds of local measurements. When the boundaries are divided into low‐ and high‐resistance groups, statistically significant differences in rotation axis and angle distributions are found. The misorientation distribution of the low‐resistance boundary group is suggested to reflect the low‐energy configurations of boundary planes in MnZn ferrites.

On the localized impedance spectroscopic characterization of grain boundaries: General aspects and experiments on undoped SrTiO3

“…(Please note that in Eq. (14) of Ref. 2 the ratio of relaxation frequencies should be replaced by its inverse value.)…”

“…Therefore, recent papers also dealt with the impedance spectroscopic analysis of grain boundaries in Fe-doped SrTiO 3 or Mn-Zn-ferrites using microelectrodes. 13,14 Finite element calculations on the impedance between microelectrodes can then help interpret local measurements. 15 Such simulations quantitatively showed how far other grain boundaries close to the investigated one also influence the measurement results.…”

Distribution of Σ3 misorientations in polycrystalline strontium titanate

“…A common strategy for analyzing this 3-D data is to project it into one-dimensional space (misorientation angle) 29,30 or 2-D space (misorientation axis). 22,28,31 In this study, the grain misorientations are displayed in misorientation axis and angle space separately to obtain the misorientation axis and angle distributions for texture analysis.…”

Advanced microstructural analysis of ferrite materials by means of electron backscatter diffraction (EBSD)

“…The M-type hexaferrite BaFe 12 O 19 (Ba-ferrite) samples are conventional bulk samples [16,17]. Sample A was prepared using solid-state reaction, while for sample B a magnetic field was applied to produce a grain orientation.…”