Self-Biased 215MHz Magnetoelectric NEMS Resonator for Ultra-Sensitive DC Magnetic Field Detection

Abstract

High sensitivity magnetoelectric sensors with their electromechanical resonance frequencies < 200 kHz have been recently demonstrated using magnetostrictive/piezoelectric magnetoelectric heterostructures. In this work, we demonstrate a novel magnetoelectric nano-electromechanical systems (NEMS) resonator with an electromechanical resonance frequency of 215 MHz based on an AlN/(FeGaB/Al2O3) × 10 magnetoelectric heterostructure for detecting DC magnetic fields. This magnetoelectric NEMS resonator showed a high quality factor of 735, and strong magnetoelectric coupling with a large voltage tunable sensitivity. The admittance of the magnetoelectric NEMS resonator was very sensitive to DC magnetic fields at its electromechanical resonance, which led to a new detection mechanism for ultra-sensitive self-biased RF NEMS magnetoelectric sensor with a low limit of detection of DC magnetic fields of ~300 picoTelsa. The magnetic/piezoelectric heterostructure based RF NEMS magnetoelectric sensor is compact, power efficient and readily integrated with CMOS technology, which represents a new class of ultra-sensitive magnetometers for DC and low frequency AC magnetic fields.

Probing electric field control of magnetism using ferromagnetic resonance

“…Multiferroic materials with simultaneous ferroelectricity and magnetism provide a pathway to achieving strong magnetoelectric coupling with efficient voltage control of magnetism, and compact and power-efficient electric field-tunable magnetic devices [1][2][3][4] . A variety of 'magnetoelectric-multiferroics' such as magnetic/ferroelectric [5][6][7][8][9][10][11][12] and magnetic/multiferroic [13][14][15][16][17] heterostructures have been investigated, which are providing pathways to novel electric field-tunable radio frequency (RF)/microwave signal processing devices 5 , magnetic field sensors 6 , MERAM devices 7 and voltagetunable magnetoresistance devices 8 .…”

“…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 .…”

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components

“…109,117,118 The ME effect offers an alternative passive approach to magnetic field sensing and the effect is largest for composites consisting of piezoelectric and magneto-strictive layers laminated together, in either longitudinal-transverse (L-T) or longitudinallongitudinal (L-L) vibration modes. At 1 Hz, the sensitivity limit to minute magnetic field variations was about 5 pT/Hz 1/2 .…”

“…109,117,118 A majority of these are made of ferromagnetic and ferroelectric layers. The coupling between the two subsystems, termed ME interaction, is mediated by mechanical strain.…”

“…Some recent studies show comparable sensitivities in miniature sensors of piezoelectric AlN-ferromagnetic alloys. 109,118 3. Broadband miniaturized antenna structures utilizing magneto-electric materials Antenna miniaturization has been the subject of interest for more than half a century, but in recent years, it has received significant attention because of additional demand for numerous mobile communication systems on a single platform.…”