Room-temperature magnetoelectric effects in multiferroic Y-type hexaferrites

Abstract

Y-type hexaferrites are promising single-phase multiferroics where the electric polarization is induced by conical spin orders. The influence of substitution of Sr and Ni on the magnetic and magnetoelectric properties of Y-type hexaferrite BaSrCo2Fe11AlO22 has been investigated. Sr doping does not change much the Curie temperature TC near 760 K and the saturation magnetization at 300 K. In contrast, the saturation magnetization is reduced by Ni doping. The spin-induced electric polarization can be reversed by a low magnetic field for all samples, and the doping has almost no influence on the magnetoelectric coefficient at room temperature. The magnetoelectric phase diagrams of all samples have been obtained by the measurements of magnetic field dependence of the dielectric constant at selected temperatures. Both Sr and Ni doping broaden the region of ferroelectric phase by driving the phase boundary to higher magnetic fields.

Ferrite Materials Containing Kagomé Layers: Chemistry of Ba2Fe11Ge2O22 and K2Co4V9O22 Hexaferrites

“…The higher magnetic ordering temperature of II relative to the Ba 2 Sn 2 MFe 10– x Ga x O 22 series can be attributed to the isolation of the magnetic layers by the nonmagnetic germanates as well as a lack of nonmagnetic ion mixing onto the magnetic sites. Other hexaferrites exhibiting relatively high temperature ordering include Ba 2 Co 2 Fe 12 O 22 at 613 K, Ba 2 Co 1.5 Ni 0.5 Fe 12 O 22 at 718 K, and BaSrCo 2 Fe 11 AlO 22 at 760 K . The exceptionally high ordering temperature of 855 K in Ba 2 Fe 11 Ge 2 O 22 is in line with that observed in some other Fe rich ferrites.…”

Mechanical Properties of Cubic‐BN(111) Bulk Single Crystal Evaluated by Nanoindentation

“…Our hardness and Young's modulus results and previously reported values for c-BN are summarized in Table 1. [20][21][22][23][24][25][26][27] Similar summary for w-BN has been provided in our previous paper. [15] There have been several experimental and calculated reports of the mechanical properties of c-BN sintered compacts but few reports of those properties for c-BN single crystals.…”

Room-temperature giant magnetotranstance effect in single-phase multiferroics

“…In these multiferroic hexaferrites, a small P is usually induced by the transverse conical spin structure in the hexagonal plane, which can be well interpreted by the spin current model [25] or inverse Dzyaloshinskii-Moriya (DM) interaction [26]. Our recent study showed that the Y-type hexaferrites BaSrCo2Fe11AlO22 and Ba0.9Sr1.1Co2Fe11AlO22 exhibit the ME effect even at room temperature [27]. Therefore, we used these samples to test the magnetic field dependence of αE at room temperature.…”