USA As Represented by Secretary of the Navy

University System of Maryland

Peter Finkel

Margo Staruch

Ahmed H Amin

Colin J Murphy

Lynn T Antonelli

Fletcher A Blackmon

Kim C Benjamin

Marilyn Wun-Fogle

James B Restorff

Christopher M Spillmann

Jakub Kolacz

Ichiro Takeuchi

Jeffrey W Baldwin

Alex E Moser

Bernard R Matis

Ronald Lacomb

Konrad Bussmann

Steven P Bennett

Julie Lacomb

Joseph J Stace

William Zappone

Meredith Metzler

Christopher S Lynch

Norman Gottron

Wen D Wong

Huilong Hou

Julia Pavlova

Thomas Mion

Piezo-optic transducers convert variations in mechanical stress to a change in optical properties by coupling electro-optic and piezo-electric elements in a format suited to a single composite device without needing on-board electronics.

Piezo-electro-optic composite transduction devices

The present invention provides a magnetoelectric multiferroic, time-variable magnetic field transmitter based upon a resonant structure capable of enhancing the transmitted field at the structural resonant frequency. This transmitter utilizes a single crystal piezoelectric as the source of mechanical excitations with a laminated transduction element to reduce eddy currents in the magnetostrictive material thereby reducing losses at higher frequencies. The structural resonance frequency can be tuned by adjusting the size of the masses, position and strength of bias magnets, pre-stress conditions and physical parameters of the transduction column elements.

Portable resonant multiferroic magnetoelectric antenna for ULF/VLF communication

A cooling system employs at least one composite elastocaloric device. Each composite device has a first member with a first material and a second member with an elastocaloric material. The first material increases in size in response to an applied electric or magnetic field and returns to its prior size upon removal of the applied electric or magnetic field. The first and second members are mechanically coupled together such that the increase in size of the first material applies a stress to the elastocaloric material and the return of the first material to its prior size releases said stress, thereby causing the elastocaloric material to absorb heat.

Systems and methods for cooling using a composite elastocaloric device

A high-sensitivity and ultra-low power consumption magnetic sensor using a magnetoelectric (ME) composite comprising of magnetostrictive and piezoelectric layers. This sensor exploits the magnetically driven resonance shift of a free-standing magnetoelectric micro-beam resonator. Also disclosed is the related method for making the magnetic sensor.

Ultra-low power magnetoelectric magnetic field sensor

Described herein is the use of large phase transformational strain in relaxor ferroelectric single crystals for broadband sound generation. The technique exploits the thermo-optical triggering and thus an opto-acoustic effect of ferroelectric phase transformation piezocrystals under mechanical bias conditions.

Thermo-optical method of phrase transformational transduction

An energy harvesting device for harvesting energy from a moving structure includes a housing allowing transmission of magnetic fields therethrough. A piezoelectric material capable of a phase transition and a magnetostrictive material capable of a structural change when subjected to a magnetic field are mechanically coupled to each other in the housing. An adjustable pre-stress means is positioned between the housing and the combination of the piezoelectric and magnetostrictive materials. Electrical contacts are positioned on the piezoelectric material. A magnet is mounted on the moving structure. The housing is mounted in sufficient proximity to the magnet for the magnetic field of the magnet to induce the structural change in the magnetostrictive material.

Magnetoelectric energy harvesting

A transducer for generating electrical energy from an expected force includes a single crystal ferroelectric material having a phase transition stress level. Mechanical stress is provided to this crystal at a level approaching the phase transition stress level, such that the expected external force will cause the phase transition. At least two electrodes are joined to the single crystal for receiving electrical energy created by the phase transition. The electrodes can be joined to conditioning and storage circuitry. In further embodiments, the phase transition is induced by an expected temperature change.

Energy harvesting utilizing stress induced phase transformation in ferro-electric piezocrystals

A piezoelectric transducer includes a single crystal piezoelectric material having a phase transition from one crystalline phase to a second crystalline phase at a predetermined stress level. A pre-stress is applied to the single crystal piezoelectric material so that the material is maintained near its phase transition point. An electrical field source is joined to the material such that, in cooperation with the pre-stress, an increase or decrease in the electrical field causes a crystalline phase transition in the single crystal piezoelectric material. Crystalline phase transition induces strain larger by an order of magnitude than that caused by the non-phase transition piezoelectric effect.

Crystalline relaxor-ferroelectric phase transition transducer

Growing community of inventors

Baltimore, MD, United States of America

Peter Finkel