Nonlinear magnetoelectric effects in Y-type hexaferrite microwave resonators

Abstract

The nature of the nonlinear magnetoelectric effect is investigated in platelets of single-crystal Y-type hexaferrite with a collinear ferrimagnetic structure. The effect was observed at room temperature as a shift of 1.1-to-1.4 GHz in the ferromagnetic resonance frequency of Ba2Zn2Fe12O22 (Zn2Y) rectangular resonator with the application of an in-plane DC voltage. The shift amounted to 10%–12% of the central frequency which ranged from 8 to 17 GHz (X and Ku-bands). From the experimental results, we estimated the magnetoelectric modification of effective saturation magnetization and found that it scales almost linearly with the applied DC electric power. A phenomenological model for the nonlinear magnetoelectric effect, which considers the hexaferrite magnetic symmetry, is proposed and qualitatively accounts for the observed dependence of magnetic parameters on input power. It is shown that the resonator can operate as an electrically controlled discrete phase shifter with almost π/4 phase shift and <4 dB insertion losses. These results are of importance for the use of Y-type hexaferrites in electrically tunable planar microwave signal processing devices.

Quadratic magnetoelectric effect during field cooling in sputter grown Cr$_2$O$_3$ films

“…We estimate β = −1.69 × 10 −18 s A −1 , based on our previous estimation of microscopic α = 27 × 10 −12 s m −1 [26]. In other multiferroic materials, such as NiSO 4 • 6H 2 O [56] and BiFeO 3 [57], the magnitude of β is comparable to our observation, albeit reported at low temperatures of 3-4 K. Other multiferroics with a non-collinear spin structure have a large quadratic ME effect, observed at very low temperatures and high fields [10,12,[58][59][60]. The microscopic mechanism of the quadratic ME effect in a collinear ferrimagnet requires further investigation.…”

Y-type Hexagonal Ferrite-based Band-Pass Filter with Dual Magnetic and Electric Field Tunability

“…2. The magnetic and electric parameters used for simulation were the following: 4πMS=2300 G [23], dielectric constant ε=12, and ferromagnetic linewidth ΔH=15 Oe [29]. Since HFSS cannot correctly account for the easy plane uniaxial anisotropy, the value of Ha was not included in the simulation.…”

“…When the bias field is measured outside The sample, the difference between the value registered by the Gaussmeter and the actual field at the position of ferrite resonator would be different for any meaningful comparison. We therefore estimated H0 values by using data in Figure 4 on resonance frequency as a function of the bias field produced by an electromagnet for a sample of Zn2Y of identical dimensions as the platelet used in the filter [23]. The bias fields H0 in Fig.…”

“…As it was demonstrated in Ref. [23] the application of DC electric current to hexaferrite sample results in strong modification of "effective" magnetization 4…”

Y-type hexagonal ferrite-based band-pass filter with dual magnetic and electric field tunability

“…This work is on a dual magnetic field and electric field tunable Y-type hexagonal ferrite filter. The magnetic field H tuning of the filter was accomplished with a built-in permanent magnet and the electric field E tuning was facilitated by the recently reported nonlinear magnetoelectric (NLME) effect in M- and Y-type hexagonal ferrites 22 , 23 . Application of a pulsed or DC electric field to the ferrite was found to result in variations in the magnetization and magnetocrystalline anisotropy field and the changes in these order parameters were proportional to E 2 .…”