Room temperature magnetoelectric effects in bulk poly-crystalline materials of M- and Z-type hexaferrites

Abstract

The converse magnetoelectric effect in poly-crystalline Z-type, Sr3Co2Fe24O41, and M-type, SrCo2Ti2Fe8O19 (SCTFO), hexaferrite materials are reported. The change in remanent magnetization (Mr) for M-SCTFO sintered in oxygen and sintered in air is similar and approximately equals to ∼3% in 13 kV/cm electric field and for Z-type is ∼12% in ∼10 kV/cm electric field. The measured magnetoelectric coupling coefficient, α, values at room temperature for Z-type and M-type hexaferrites sintered in O2 were measured to be 7.6 × 10−10 sm−1 and 2.4 × 10−10 sm−1, respectively. Sintering the M-type in air reduced to 1.7 × 10−10 sm−1. As it is well known, lack of oxygen in local oxygen sites implies lower resistivity and a modified magnetic structures or state. However, in magnetoelectric hexaferrites, there is an additional effect due to lack of oxygen, and the spin spiral configuration is significantly modified to lower the induced magnetization upon the application of a DC voltage or electric field.

Negative differential resistance: Another banana?

“…1 indicate that the NDR effect is caused by water molecules in the ambient or moist environments and independent of gas type. For comparison, all of the published results for Sr 3 Co 2 Z show a linear σ -E relation [24,25,32,33]. The difference could be attributed to the lower electric fields applied in them than in this work.…”

Magnetoelectric excitations in hexaferrites utilizing solenoid coil for sensing applications

“…Recently, single phase magnetoelectric (ME) hexaferrites [1][2][3][4] have exhibited high ME coupling, α, at room temperature. As such, there appears to be potential to develop and fabricate novel devices based on the ME effect.…”

Electronic Structure and Magnetic Properties of FeTe, BiFeO3, SrFe12O19 and SrCoTiFe10O19 Compounds

“…Hexaferrites SrFe 12 [14,15]. The aim of the present investigation was, firstly, to find a reliable approach of DFT to describe properly electronic structure and magnetism of SrFe 12 O 19 , and then, using this approach, to explore electronic structure and magnetic properties of SrFe 12 O 19 -based systems where Fe is substituted with Ti and Co atoms.…”

“…There is renewed interest in properties of such iron oxides as BiFeO 3 -and M Fe 12 O 19 -based systems [7][8][9][10][11][12][13][14][15]. BiFeO 3 is antiferromagnetic and multiferroic, whereas M Fe 12 O 19 (M = Sr, Ba, Pb) are ferrimagnetic systems with expected manifestation of multiferroic properties.…”