Exemplary practice of the present invention provides a magnetostrictive actuator characterized by linear force output and uniform magnetic biasing. A center bias magnet drives flux through series magnetostrictive bars in opposite directions while surrounding drive coils apply flux in the same direction through the bars. The net response is substantially linear with respect to the drive coil current. A second parallel set of magnetostrictive bars completes the flux path and adds to the actuator output force. Flux leakage between the parallel bars is compensated by a ferromagnetic shunt or by a tapered magnet providing uniform flux density down the length of the magnetostrictive bars. The closed flux path allows magnetic shielding of the entire actuator, if desired.

The disclosure describes new apparatus, systems and methods utilizing magnetoelectric neural stimulators with tunable amplitude and waveform. Specific embodiments of the present disclosure include a magnetoelectric film, a magnetic field generator and an electrical circuit coupled to the magnetoelectric film, in particular embodiments, the electrical circuit comprises components configured modify an electrical output signal produced by the magnetoelectric film. In certain embodiments, the electrical circuit is configured to modify the electric signal to charge a charge storage element, to transmit data to an implantable wireless neural stimulator, and to provide a stimulation output to electrodes.

A magneto-electric converter capable of converting a variation in magnetic field into a potential difference between two electrical terminals includes a support layer comprising two electrical terminals; a stack disposed on the support layer of a first layer made from a magnetostrictive material defining the reference plane and of a second layer made from a piezoelectric material having a polarization axis in the plane defined by the second layer, parallel to the reference plane; the second layer comprising electrodes; and a means for electrical connection of the electrodes to the electrical terminals.

A magnetostrictive material includes a FeGaSm alloy that is represented by Expression (1),
Fe.sub.(100-x-y)Ga.sub.xSm.sub.y  (1) (in Expression (1), x and y are respectively a content rate (at. %) of Ga and a content rate (at. %) of Sm, and satisfy that y≤0.35x−4.2, y≤−x+20.1, and y≥−0.1x+2.1).

Magnetoelectric devices based on piezoelectric/magnetostrictive bilayers are provided. Also provided are methods of using the devices to modulate or to sense the magnetization of the magnetostrictive material. The devices include an island of magnetostrictive material that is strain-coupled to a thin layer of a piezoelectric material at an interface. A bottom electrode is placed in electrical communication with one surface of the piezoelectric film, and an unpaired top electrode is placed in electrical communication with a second, opposing surface of the piezoelectric film.

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.

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.

There is provided a magnetic deformable member that is deformable upon application of magnetism, and that has a front surface that projects toward the side opposite to a magnet when such a magnet is placed. The front surface provides variations in tactile feel or viewability for humans by providing a soft tactile feel. A magnetic deformable member includes: a flexible sheet; a back plate made of a hard material and stacked on the flexible sheet; a gel charged inside a space between the flexible sheet and the back plate; and a magnetic member having an annular shape as viewed in plan in a direction that is perpendicular to a front surface of the flexible sheet and having a length in the perpendicular direction. The magnetic member is secured to the flexible sheet, and disposed in the gel.

A magnetic sensor includes a piezomagnetic component which includes a first piezomagnetic element and a second piezomagnetic element that are arranged opposite to each other, a magnetostrictive component which includes a first magnetostrictive element and a second magnetostrictive element arranged opposite to each other on the same side of the first piezomagnetic element and the second piezomagnetic element, respectively, and a piezoelectric component which includes a first piezoelectric element deposited underneath the first piezomagnetic element, a second piezoelectric element deposited underneath the second piezomagnetic element, a third piezoelectric element deposited underneath the first magnetostrictive element, and a fourth piezoelectric element deposited underneath the second magnetostrictive element. The first piezoelectric element and the second piezoelectric element are electrically connected to a power supply circuit, and produce first deformation, which is applied to the first piezomagnetic element and the second piezomagnetic element to produce an alternating magnetic field.

Active-mode sensors are provided, and may be used to detect air, water, and sediment interfaces. Systems and methods for sensing air, water, and sediment are also provided. The sensors are robust and withstand forces due to moving or shifting water and sediment.