Fabrication and characterization of all-thin-film magnetoelectric sensors

Abstract

ac magnetic field sensors based on thin-film magnetoelectric ͑ME͒ devices operating at room temperature have been fabricated. The ME layers consist of a sol-gel derived Pb͑Zr 0.52 Ti 0.48 ͒O 3 film and a sputter deposited Fe 0.7 Ga 0.3 film on Si cantilevers. The ME coupling is substantially improved by depositing a Pt layer at the interface. The ME coefficient up to 1.81 V / Oe cm is obtained at the mechanical resonant frequency of 333 Hz and at dc bias magnetic field of 90 Oe. Clear reduction in the substrate clamping effect is observed as the Si cantilever thickness is systematically reduced down to 35 m.

Probing electric field control of magnetism using ferromagnetic resonance

“…The above experimental observations cannot be explained by conventional magnetoelectric coupling mechanisms, such as charge-mediated magnetoelectric coupling [20][21][22][23] , or strainmediated magnetoelectric coupling [10][11][12][18][19] , for the following reasons. The IP anisotropic FMR field dependence on applied voltage along different magnetic field orientations is not likely to originate from interfacial charge-screening effects [20][21][22][23] , even though the BFO layer has a high polarization.…”

“…Several magnetoelectric coupling mechanisms have been explored to achieve efficient electric field control of magnetism, for example, strain-mediated magnetoelectric coupling [9][10][11][12]18,19 , spin-polarized charge-mediated magnetoelectric coupling [20][21][22][23][24][25] and voltage control of carrier-mediated magnetism in dilute magnetic semiconductors [26][27][28] . Strain-mediated magnetoelectric coupling in thin-film magnetic/ferroelectric heterostructures on substrates can be diminished due to substrate clamping effects 6,18,19 , while spin-polarized charge-mediated magnetoelectric coupling can only be observed in ultra-thin (o1 nm) magnetic thin films [20][21][22][23][24][25] , which puts a limit on its application in real magnetoelectric devices.…”

“…Strain-mediated magnetoelectric coupling in thin-film magnetic/ferroelectric heterostructures on substrates can be diminished due to substrate clamping effects 6,18,19 , while spin-polarized charge-mediated magnetoelectric coupling can only be observed in ultra-thin (o1 nm) magnetic thin films [20][21][22][23][24][25] , which puts a limit on its application in real magnetoelectric devices. Finally, voltage control of carriermediated magnetism in dilute magnetic semiconductors has been challenging at room temperature 26,28 .…”

Voltage control of magnetism in multiferroic heterostructures

“…Most recently, we reported a new class of microwave magnetic thin-film materials, FeGaB films, which have large magnetostriction constant and low saturation fields desired for multiferroic composite applications [38]. With changing the B doping level, amorphous phase FeGaB was produced and led to excellent magnetic softness with coercivity less than 1 Oe, narrow FMR linewidth of [16][17][18][19][20] Oe at X-band (9.6 GHz), large λ s of 50-70 ppm, high saturation magnetization of 11-15 kG, and a self-biased FMR frequency of 1.85 GHz. The combination of these properties makes the FeGaB films potential candidates for tunable ME microwave devices and other RF/microwave magnetic device applications.…”

Giant magnetostriction in annealed Co1−xFex thin-films

“…In this study, we investigate the composition and thermal process dependent magnetostrictive and microstructural properties of Co 1 − x Fe x alloy thin films, prepared using a co sputtering based composition spread approach 16,[35][36][37] . This technique facilitates syn thesis and screening of large compositional landscapes in indi vidual studies and allows rapid identification of compositions with enhanced physical properties.…”