Magnetoelectric interactions in layered composites of piezoelectric quartz and magnetostrictive alloys

Abstract

Mechanical strain mediated magnetoelectric effects are studied in bilayers and trilayers of piezoelectric quartz and magnetostrictive permendur (P), an alloy of Fe-Co-V. It is shown that the magneto-electric voltage coefficient (MEVC), proportional to the ratio of the piezoelectric coupling coefficient to the permittivity, is higher in quart-based composites than for traditional ferroelectrics based ME composites. In bilayers of X-cut single crystal quartz and permendur, the MEVC varies from 1.5 V/cm Oe at 20 Hz to ~ 185 V/cm Oe at bending resonance or electromechanical resonance corresponding to longitudinal acoustic modes. In symmetric X-cut quartz-P trilayers, the MEVC ~ 4.8 V/cm Oe at 20 Hz and ~ 175 V/cm Oe at longitudinal acoustic resonance. Trilayers of Y-cut quartz and permendur show ME coupling under a shear strain with an MEVC that is an order of magnitude smaller than for longitudinal strain in samples with X-cut quartz. A model for low-frequency and resonance ME effects which allows for explicit expressions of MEVC and resonance frequencies is provided and calculated MEVC are in general 2 agreement with measured values. Magneto-electric composites with quartz have the desired characteristics such as the absence of ferroelectric hysteresis and pyroelectric losses and could potentially replace ferroelectrics in composite-based magnetic sensors, transducers and high frequency devices.

Anisotropy of the magnetoelectric effect in tri-layered composites based on single-crystalline piezoelectrics

“…The properties of some bulk tri-layered composites found in the literature with equivalent structures but employing different compounds are also listed. By comparison, we conclude that the 249 V/(cm·Oe) coefficient observed in the LNO sample is one of the largest ever found in ME 2-2 bulk tri-layered structures, being even larger than the 175 V/(cm·Oe) value measured in a Permendur/Quartz/Permendur system [15]. It is also remarkably larger than those found in lead-based PMN-PT (70 V/(cm·Oe)) and PZT (110 V/(cm·Oe)) composites with Permendur [19].…”

“…Nonetheless, other alternative crystalline lead-free PEs have been explored with the potential to yield a comparably large direct ME coupling in composites. Such systems have included quartz [15], aluminum nitride [14], zinc oxide [18], langatate (La 3 Ga 5.5 Ta 0.5 O 14 , LGT) [19,20] and langasite La 3 Ga 5.5 SiO 14 , LGS) [20]. We have recently shown the same could apply to tri-layered composites featuring crystalline lithium niobate (LiNbO 3 , LNO) [21].…”

“…As for the PE phase, ferroelectric ceramics of PZT (Pb(Zr,Ti)O 3 ) have been extensively studied and tend to provide a strong ME coupling due to their relatively large piezoelectric and electromechanical (EM) coupling coefficients [11][12][13]. The use of highly anisotropic single crystalline ferroelectrics, poled and cut along desirable crystallographic directions, is another way of achieving large but also directionally dependent ME effects [14,15]. Here, research on ME composites has been notably focused on lead-based compounds such as PMN-PT or PZN-PT [1,3,16,17].…”

Measuring the magnetoelectric effect across scales

“…For example for quartz, which we use daily in our watches, polishing out the appropriate crystal geometry determines the resonance frequency practically entirely [85]. For magnetoelectrics, the additional magnetic component can be accessed indirectly from very well knowing the specifics of a piezoelectric resonator and then measuring the resonance behavior of a (mostly used 2-2-) composite [86]. Some modeling is needed to resort the parameters of the magnetic component.…”

Direct and converse magnetoelectric effects in Metglas/LiNbO3/Metglas trilayers

“…Due to these factors, other single crystalline ferroelectrics or just piezoelectrics are being tested at present. 24,31 Another useful alternative is lithium niobate (LiNbO 3 , LNO), 32 an uniaxial ferroelectric with a very high Curie temperature (1500 K). Among other attractive features, one should note its relatively low price, high chemical, thermal, and mechanical stability, availability of big crystals of sufficiently high quality and, last but not least, its lead-free composition.…”