Browsing by Author "Xing, Zengping"

Now showing 1 - 17 of 17
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    Comparison of noise floor and sensitivity for different magnetoelectric laminates
    Gao, Junqi; Das, Jaydip; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (American Institute of Physics, 2010-10-15)
    We present a comparison of the magnetoelectric (ME) response and magnetic-field sensitivities of engineered laminate sensors comprised of magnetostrictive and piezoelectric phases. The ME voltage coefficients for Metglas and single crystal fibers of Pb(Mg1/3Nb2/3) O-3-PbTiO3 (PMN-PT) or Pb(Zn1/3Nb2/3) O-3-PbTiO3 (PZN-PT) are about 2.8 times larger than those with Metglas-Pb(Zr, Ti)O-3 (PZT) ceramic ones. This results in a 1.7 times enhancement in the magnetic-field sensitivity for the structures with single crystals. Accordingly, the noise floors are about three to four times lower for composites with PMN-PT or PZN-PT fibers than those with PZT. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3486483]
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    Detection of pico-Tesla magnetic fields using magneto-electric sensors at room temperature
    Zhai, Junyi; Xing, Zengping; Dong, Shuxiang; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2006-02-01)
    The measurement of low-frequency (10(-2)-10(3) Hz) minute magnetic field variations (10(-12) Tesla) at room temperature in a passive mode of operation would be critically enabling for deployable neurological signal interfacing and magnetic anomaly detection applications. However, there is presently no magnetic field sensor capable of meeting all of these requirements. Here, we present new bimorph and push-pull magneto-electric laminate composites, which incorporate a charge compensation mechanism (or bridge) that dramatically enhances noise rejection, enabling achievement of such requirements. (c) 2006 American Institute of Physics.
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    Direct measurement of magnetoelectric exchange in self-assembled epitaxial BiFeO3-CoFe2O4 nanocomposite thin films
    Yan, Li; Xing, Zengping; Wang, Z. G.; Wang, T.; Lei, G. Y.; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2009-05-01)
    We report the direct measurement of a magnetoelectric (ME) exchange between magnetostrictive CoFe2O4 nanopillars in a piezoelectric BiFeO3 matrix for single-layer nanocomposite epitaxial thin films grown on (001) SrTiO3 substrates with SrRuO3 bottom electrodes. The ME coefficient was measured by a magnetic cantilever method and had a maximum value of similar to 20 mV/cm Oe. The films possessed saturation polarization (60 mu C/cm(2)) and magnetization (410 emu/cc) properties equivalent to bulk values, with typical hysteresis loops.
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    Enhancement in the field sensitivity of magnetoelectric laminate heterostructures
    Das, J.; Gao, J.; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2009-08-01)
    The effect of magnetostrictive layer thickness on the magnetoelectric (ME) response and field sensitivity of Pb(Zr,Ti)O(3)-metglas based sandwiched ME heterostructures has been studied. Such structures hold promise for sensor applications. The increase in metglas thickness results in a significant increase in the ME response and magnetic field sensitivity. The ME coefficient and field sensitivity increase by about 1.5-1.75 and 2.7 times, respectively, for a structure with 150 mu m thick six metglas layers on both sides of the Pb(Zr, Ti)O(3), in comparison to a 50 mu m thick two layered structure. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3222914]
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    Extremely low frequency response of magnetoelectric multilayer composites
    Dong, Shuxiang; Zhai, Junyi; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2005-03-01)
    A promising generation of extremely low frequency magnetic field sensors, based on multilayer composites (MLCs) of magnetostrictive Terfenol-D, (Tb(1-x)Dy(x)Fe(2-y)) and piezoelectric Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3), has been developed. Our MLC magnetoelectric sensor presently shows a limit in (i) working frequency of similar to 5 x 10(-3) Hz; and (ii) magnetic field sensitivity of 10(-7), 10(-9), and 10(-11) T for frequencies of f = 10(-2), 1, and 10(2) Hz, respectively. The results open up possibilities for sensitive low frequency passive magnetic anomaly detection. (c) 2005 American Institute of Physics.
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    Geomagnetic sensor based on giant magnetoelectric effect
    Zhai, Junyi; Dong, Shuxiang; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2007-09-01)
    Here, the authors report a new type of geomagnetic field sensor based on the giant magnetoelectric effect in Metglas/piezoelectric-fiber laminates that are wrapped with a coil. These sensors can measure quite precisely the value of both the Earth's magnetic field and its inclination. The geomagnetic field sensor does not require a dc magnetic bias and is driven by a 10 mA ac. Highly sensitive dc magnetic field variations of less than 10(-9) T and angular inclinations of <= 10(-5) deg can be detected, potentially offering opportunities for a small global positioning device. (c) 2007 American Institute of Physics.
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    Giant magnetoelectric effect (under a dc magnetic bias of 2 Oe) in laminate composites of FeBSiC alloy ribbons and Pb(Zn-1/3,Nb-2/3)O-3-7%PbTiO3 fibers
    Dong, Shuxiang; Zhai, Junyi; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2007-07-01)
    Giant magnetoelectric (ME) voltage and charge coefficients have been found in long-type composites of high-permeability magnetostrictive FeBSiC alloy ribbons laminated together with piezoelectric Pb(Zn-1/3,Nb-2/3)O-3-7%PbTiO3 single crystal fibers. The maximum ME voltage and charge coefficients at low frequencies were 10.5 V/cm Oe and 1 nC/Oe under a notably low dc magnetic bias of 2 Oe; at resonance, these coefficients were dramatically increased to 400 V/cm Oe and 42 nC/Oe, respectively. These values are much higher, and the required dc magnetic bias much lower, than those of previously reported Terfenol-D based ME laminates. (C) 2007 American Institute of Physics.
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    Giant magnetoelectric effect in Metglas/polyvinylidene-fluoride laminates
    Zhai, Junyi; Dong, Shuxiang; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2006-08-01)
    Here, the authors report thin (< 100 mu m) and flexible magnetoelectric (ME) composites consisting of Metglas (high-mu magnetostriction) and polyvinylidene-fluoride (piezopolymer) layers laminated together. Both unimorph and three-layer configurations have been studied. The authors find that these ME laminates (i) require dc magnetic biases as low as 8 Oe to (ii) induce giant ME voltage coefficients of 7.2 V/cm Oe at low frequencies, and up to 310 V/cm Oe under resonant drive. (c) 2006 American Institute of Physics.
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    Giant magnetoelectric effect in Pb(Zr,Ti)O(3)-bimorph/NdFeB laminate device
    Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2008-07-01)
    A Pb(Zr,Ti)O(3)-bimorph/NdFeB laminate device has a giant magnetoelectric (ME) effect. Our results reveal a giant ME coefficient of 16 V/cm Oe or 62 nC/cm Oe at a low (subresonant) frequency of 10 Hz, and one of 250 V/cm Oe or 960 nC/cm Oe at a first order resonant bending mode frequency of similar to 60 Hz. The findings show a simple means by which to achieve magnetoelectric effects, without the use of magnetostrictive material. (C) 2008 American Institute of Physics.
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    Giant magnetoelectric torque effect and multicoupling in two phases ferromagnetic/piezoelectric system
    Xing, Zengping; Xu, Kai; Dai, Guangyu; Li, Jiefang; Viehland, Dwight D. (American Institute of Physics, 2011-11-15)
    The physical mechanism of a non-magnetostrictive magnetoelectric (ME) effect was revealed and designated as the ME torque (MET) effect. Experimental results showed that the MET effect could be huge; a simple MET device could achieve giant ME voltage coefficients of 100 V/cm. Oe at 1Hz and 2100 V/cm. Oe at the first order resonant frequency. These are the highest reported ME coefficients in a bulk device ever. We then proposed the multicoupling ME effect, which comes from the interaction of magnetostriction, magnetic torque, and piezoelectricity, and rewrite the ME constitutive tensor equation. The abnormal phenomenon in the (1-3) structure ME thin film that T-L mode might bring larger ME coupling than L-L mode was successfully explained from the multicoupling concept. These researches have extended the giant ME effect from the traditional magnetostrictive/piezoelectric system to a common ferromagnetic/piezoelectric system, and gave more choices to scientists/engineers for constructing the giant ME device. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662912]
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    Investigation of external noise and its rejection in magnetoelectric sensor design
    Xing, Zengping; Zhai, Junyi; Li, Jiefang; Viehland, Dwight D. (American Institute of Physics, 2009-07-15)
    Laminated magnetoelectric (ME) composites consisting of magnetostrictive and piezoelectric layers are an important class of magnetic sensors. Here, we will present a means to design ME sensors with in-built capabilities to cancel environmental noise, based on designing the sensor signal and the noise in different fundamental modes. We then show that some composite designs offer unique capabilities to reject acoustic or thermal noise sources. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3176500]
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    Magnetoelectric and multiferroic properties of variously oriented epitaxial BiFeO3-CoFe2O4 nanostructured thin films
    Yan, Li; Wang, Zhiguang; Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (American Institute of Physics, 2010-03-15)
    We report the ferroelectric, ferromagnetic, and magnetoelectric (ME) properties of self-assembled epitaxial BiFeO3-CoFe2O4 (BFO-CFO) nanostructure composite thin films deposited on (001), (110), and (111) SrTiO3 (STO) single crystal substrates. These various properties are shown to depend on orientation. The maximum values of the relative dielectric constant, saturation polarization, longitudinal piezoelectric coefficient, saturation magnetization, and ME coefficient at room temperature were 143, 86 mu m/cm(2), 50 pm/V, 400 emu/cc, and 20 mV/cm Oe, respectively.
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    Magnetoelectric Device and the Measurement Unit
    Xing, Zengping (Virginia Tech, 2009-04-10)
    Magnetic sensors are widely used in the field of mineral, navigational, automotive, medical, industrial, military, and consumer electronics. Many magnetic sensors have been developed that are generated by specific laws or phenomena: such as search-coil, fluxgate, Hall Effect, anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR), magnetoelectric (ME), magnetodiode, magnetotransictor, fiber-optic, optical pump, superconducting quantum interference device (SQUID), etc. Each of these magnetic field sensors has their merits and application areas. For low power consumption (<10uW), quasi-static frequency (<10Hz) and high sensitivity (ME is the most important parameter. To enhance resonant gain in αME, I have developed a three phase laminate concept, which is based on increasing the effective mechanical factor Q while reducing the resonant frequency. A ME voltage coefficient of αME ~40V/cm.Oe has been achieved at resonance, which is about 2x higher than that of a conventional bending mode. Investigations of detection circuit optimization were also performed. Component selection strategies and a new charge topology were considered. Proper component values were required to optimize the charge detection scheme. It was also found, under some specific conditions to satisfy the circuit stability, that if the lowest required measurement frequency of the charge source was f1, then that it was not necessary to make the high corner frequency fp of the charge amplifier lower than f₁: as doing so would decrease the system's signal-to-noise ratio (SNR). A high pass, high order filter placed behind the charge amplifier was found to increase the charge sensitivity, as it narrows the intrinsic noise bandwidth and decreases the output noise contribution, while only slightly affecting the signal's output amplitude. Prototype ME unit were also constructed, and their noise level simulated by Pspice. Experimental results showed that prototypes ME unit can reach their detection limit. In addition, a new magneto-electric coupling mechanism was also found, which had a giant ME effect.
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    Modeling and the signal-to-noise ratio research of magnetoelectric sensors at low frequency
    Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2007-10-01)
    The authors have modeled magnetoelectric (ME) laminate sensor units by considering both the ME laminate and detection circuitry. Theory predicts and experiments confirm that the signal-to-noise ratio increases with increasing frequency in the low frequency range. Our findings provide useful insights into ME sensitivity estimation and "real-world" low frequency magnetic anomaly detection by ME sensors. (c) 2007 American Institute of Physics.
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    Noise and scale effects on the signal-to-noise ratio in magnetoelectric laminate sensor/detection units
    Xing, Zengping; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2007-10-01)
    We have investigated the output noise level (E-no) and signal-to-noise ratio (SNR) for various magnetoelectric (ME) laminate composites. Our findings show (i) that E-no is nearly independent of materials couple or operational mode and practically determined by the laminate capacitance C and (ii) that the SNR has a scale effect, where it is limited by the volume (V) of the piezoelectric layer. Relations between SNR, V, and the magnetoelectric coefficient (alpha ME) give insights into how to construct ME sensors with enhanced sensitivity to small magnetic variation. (C) 2007 American Institute of Physics.
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    Resonant bending mode of Terfenol-D/steel/Pb(Zr,Ti)O-3 magnetoelectric laminate composites
    Xing, Zengping; Dong, Shuxiang; Zhai, Junyi; Yan, Li; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2006-09-01)
    Resonant bending-mode Tb1-xDyxFe2-y/elastic-steel/Pb(Zr,Ti)O-3 magnetoelectric (ME) laminate composites have been investigated. An elastic-steel layer with a relatively high Q(m) significantly increases the resonant enhancement of the ME coefficient due to an increased effective Q(m) of the laminate. The three-phase ME laminates have a low first-order bending frequency of similar to 5 kHz, with a resonance-enhanced ME coefficient of similar to 40 V/cm Oe. (c) 2006 American Institute of Physics. (c) 2006 American Institute of Physics.
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    Thermal noise cancellation in symmetric magnetoelectric bimorph laminates
    Zhai, Junyi; Xing, Zengping; Dong, Shuxiang; Li, Jiefang; Viehland, Dwight D. (AIP Publishing, 2008-08-01)
    We have found a symmetric Terfenol-D/Pb(Zr,Ti)03 (PZT) bimorph magnetoelectric (ME) laminate, which operates in a bending mode under an unsymmetrical (U-shaped) magnetic bias. It has a giant ME voltage coefficient of about 70 V/cm Oe at resonance. Unlike other symmetric ME laminate structures, the symmetric bimorph structure has the capability to reject thermal noise from a magnetic signal, due to its back-to-back structure. The mechanism for the thermal noise cancellation capability is that the laminate operates in a bending mode (out charges of reverse sign), whereas the thermal noise is contained in a longitudinal mode (out charges have the same sign, allowing cancellation by differential detection). (C) 2008 American Institute of Physics.