Browsing by Author "Howe, B. M."
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- Converse magnetoelectric effects in composites of liquid phase epitaxy grown nickel zinc ferrite films and lead zirconate titanate: Studies on the influence of ferrite film parametersZhou, Peng; Popov, M. A.; Liu, Ying; Bidthanapally, Rao; Filippov, D. A.; Zhang, Tianjin; Qi, Yajun; Shah, P. J.; Howe, B. M.; McConney, M. E.; Luo, Yongming; Sreenivasulu, Gollapudi; Srinivasan, Gopalan; Page, M. R. (2019-04-09)The interactions between electric and magnetic subsystems in a ferroelectric-ferromagnetic composite occur through mechanical forces. Here we discuss results of a systematic investigation on the strength of the magnetic response of the composite to an applied electric field, known as the converse magnetoelectric (CME) effect, and its dependence on the ferroic order parameters and volume fraction for the two phases. Studies were carried out on composites of lead zirconate titanate and 2-30-mu m-thick nickel zinc ferrite (NZFO) films grown by liquid phase epitaxy on lattice matched (100) and (111) MgO substrates. Ferromagnetic resonance was utilized to determine the strength of CME from data on electric field E induced shift in the resonance frequency and its dependence on ferrite film orientation and thickness as well as MgO substrate thickness. The CME coupling coefficient A was found to be a factor of 2 to 4 higher in samples with NZFO films with (100) orientation than for (111) films. A decrease in A was measured with increasing ferrite film thickness and a very significant enhancement in the strength of CME was measured for decreasing MgO thickness. A model for CME that takes into consideration the influence of nonferroic MgO substrate was developed, and estimated A values are in very good agreement with the data. The results presented here are also of importance for a new class of electric field tunable ferrite microwave devices.
- Experimental realization of linearly polarized x-ray detected ferromagnetic resonanceKlewe, C.; Emori, S.; Li, Q.; Yang, M.; Gray, B. A.; Jeon, H-M; Howe, B. M.; Suzuki, Y.; Qiu, Z. Q.; Shafer, P.; Arenholz, E. (IOP Publishing, 2022-01-01)We present the first theoretical and experimental evidence of time-resolved dynamic x-ray magnetic linear dichroism (XMLD) measurements of GHz magnetic precessions driven by ferromagnetic resonance in both metallic and insulating thin films. Our findings show a dynamic XMLD in both ferromagnetic Ni80Fe20 and ferrimagnetic Ni0.65Zn0.35Al0.8Fe1.2O4 for different measurement geometries and linear polarizations. A detailed analysis of the observed signals reveals the importance of separating different harmonic components in the dynamic signal in order to identify the XMLD response without the influence of competing contributions. In particular, RF magnetic resonance elicits a large dynamic XMLD response at the fundamental frequency under experimental geometries with oblique x-ray polarization. The geometric range and experimental sensitivity can be improved by isolating the 2 omega Fourier component of the dynamic response. These results illustrate the potential of dynamic XMLD and represent a milestone accomplishment toward the study of GHz spin dynamics in systems beyond ferromagnetic order.