A magnetic field device determines external magnetic influence. The device has a component with ferromagnetic material. The component has one or more magnetizable tracks arranged adjacent to each other having opposing directions of magnetization and arranged axially in relation to the component. A first magnetic field sensor is arranged radially in relation to the component and is assigned to the two tracks. A second magnetic field sensor is arranged radially in relation to the component and is assignable to two magnetisable tracks. The signal of each of the magnetic field sensors is set in relation to the signal of the at least one another magnetic field sensor. The signals produced by the magnetic field sensors form at least one individual signal channel. The first and second magnetic field sensors are combined with each other axially along the direction of magnetization of the assigned magnetic track to form the signal channel.

An acoustically driven ferromagnetic resonance (ADFMR) device includes a piezoelectric element, a pair of transducers arranged to activate the piezoelectric element to generate an acoustic wave, a magnetostrictive element arranged to receive the acoustic wave, and a readout circuit to detect one of either a change in the magnetostrictive element or a change in the acoustic wave.

An acoustically driven ferromagnetic resonance (ADFMR) device includes a piezoelectric element, a pair of transducers arranged to activate the piezoelectric element to generate an acoustic wave, a magnetostrictive element arranged to receive the acoustic wave, and a readout circuit to detect one of either a change in the magnetostrictive element or a change in the acoustic wave.

An acoustically driven ferromagnetic resonance (ADFMR) device has a piezoelectric element comprised of piezoelectric material, first and second electrodes arranged in a vertical stack with the piezoelectric element to activate the piezoelectric element to generate an acoustic wave, a radio frequency voltage source electrically connected to the first electrode, a magnet comprised of a magnetostrictive material in the vertical stack with the first and second electrodes and the piezoelectric element to receive the acoustic wave, wherein the acoustic wave resonates at a ferromagnetic resonance of the magnetostrictive material, and a readout circuit to detect a change in the acoustic wave by detecting one of an output voltage amplitude, a change in impedance or a reflection of the acoustic wave in the magnet to measure an unknown magnetic field in which the ADFMR device resides and as experienced at the magnetostrictive element.

An acoustically driven ferromagnetic resonance (ADFMR) device has a piezoelectric element comprised of piezoelectric material, first and second electrodes arranged in a vertical stack with the piezoelectric element to activate the piezoelectric element to generate an acoustic wave, a radio frequency voltage source electrically connected to the first electrode, a magnet comprised of a magnetostrictive material in the vertical stack with the first and second electrodes and the piezoelectric element to receive the acoustic wave, wherein the acoustic wave resonates at a ferromagnetic resonance of the magnetostrictive material, and a readout circuit to detect a change in the acoustic wave by detecting one of an output voltage amplitude, a change in impedance or a reflection of the acoustic wave in the magnet to measure an unknown magnetic field in which the ADFMR device resides and as experienced at the magnetostrictive element.

A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, with a base plate (11) having at least one supporting/bearing/clamping point (111), at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one input coupling means (161) for microwaves and at least one output coupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another. Also, a magnetic field measuring method having a magnetic field measuring device according to the invention.

A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, with a base plate (11) having at least one supporting/bearing/clamping point (111), at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one input coupling means (161) for microwaves and at least one output coupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another. Also, a magnetic field measuring method having a magnetic field measuring device according to the invention.

A vibration powered generator capable of vibrating at a plurality of resonance frequencies to generate electric power with a simpler structure is provided. A vibration powered generator has an elongated magnetostrictive material having one end attached to a vibrating body, in which the magnetostrictive material vibrates due to vibration of the vibrating body whereby the vibration powered generator generates electric power with the aid of an inverse magnetostrictive effect of the magnetostrictive material. A cross-sectional shape vertical to a longitudinal direction of the magnetostrictive material has an asymmetrical shape with respect to a straight line extending along a vibration direction thereof due to vibration of the vibrating body.

A vibration powered generator capable of vibrating at a plurality of resonance frequencies to generate electric power with a simpler structure is provided. A vibration powered generator has an elongated magnetostrictive material having one end attached to a vibrating body, in which the magnetostrictive material vibrates due to vibration of the vibrating body whereby the vibration powered generator generates electric power with the aid of an inverse magnetostrictive effect of the magnetostrictive material. A cross-sectional shape vertical to a longitudinal direction of the magnetostrictive material has an asymmetrical shape with respect to a straight line extending along a vibration direction thereof due to vibration of the vibrating body.

A magnetic field sensor element with a piezo electric substrate having predetermined shear wave velocity V.sub.S, two pairs of interdigital electrodes, arranged on the substrate on the ends of a delay section, having a period length p of at least 10 micrometers, a non-magnetic, electrically non-conductive guide layer arranged on the substrate along the delay section, and a magnetostrictive functional layer arranged on the guide layer, wherein the shear wave velocity in the guide layer is smaller than V.sub.S, wherein a) the substrate is oriented to generate and propagate mechanical shear waves upon applying a temporally periodic, electrical voltage to at least one interdigital electrode pair in the range of frequency V.sub.S/p and, wherein b) the thickness of the guide layer equals at least 10% and at at most 30% of the period length p of the interdigital electrodes.