An improved magnetic tunnel junction with two oxide interfaces on each side of a ferromagnetic layer (FML) leads to higher PMA in the FML. The novel stack structure allows improved control during oxidation of the top oxide layer. This is achieved by the use of a FML with a multiplicity of ferromagnetic sub-layers deposited in alternating sequence with one or more non-magnetic layers. The use of non-magnetic layers each with a thickness of 0.5 to 10 Angstroms and with a high resputtering rate provides a smoother FML top surface, inhibits crystallization of the FML sub-layers, and reacts with oxygen to prevent detrimental oxidation of the adjoining ferromagnetic sub-layers. The FML can function as a free or reference layer in an MTJ. In an alternative embodiment, the non-magnetic material such as Mg, Al, Si, Ca, Sr, Ba, and B is embedded by co-deposition or doped in the FML layer.

An improved magnetic tunnel junction with two oxide interfaces on each side of a ferromagnetic layer (FML) leads to higher PMA in the FML. The novel stack structure allows improved control during oxidation of the top oxide layer. This is achieved by the use of a FML with a multiplicity of ferromagnetic sub-layers deposited in alternating sequence with one or more non-magnetic layers. The use of non-magnetic layers each with a thickness of 0.5 to 10 Angstroms and with a high resputtering rate provides a smoother FML top surface, inhibits crystallization of the FML sub-layers, and reacts with oxygen to prevent detrimental oxidation of the adjoining ferromagnetic sub-layers. The FML can function as a free or reference layer in an MTJ. In an alternative embodiment, the non-magnetic material such as Mg, Al, Si, Ca, Sr, Ba, and B is embedded by co-deposition or doped in the FML layer.

A plurality of conductive via connections are fabricated on a substrate located at positions where MTJ devices are to be fabricated, wherein a width of each of the conductive via connections is smaller than or equivalent to a width of the MTJ devices. The conductive via connections are surrounded with a dielectric layer having a height sufficient to ensure that at the end of a main MTJ etch, an etch front remains in the dielectric layer surrounding the conductive via connections. Thereafter, a MTJ film stack is deposited on the plurality of conductive via connections surrounded by the dielectric layer. The MTJ film stack is etched using an ion beam etch process (IBE), etching through the MTJ film stack and into the dielectric layer surrounding the conductive via connections to form the MTJ devices wherein by etching into the dielectric layer, re-deposition on sidewalls of the MTJ devices is insulating.

A plurality of conductive via connections are fabricated on a substrate located at positions where MTJ devices are to be fabricated, wherein a width of each of the conductive via connections is smaller than or equivalent to a width of the MTJ devices. The conductive via connections are surrounded with a dielectric layer having a height sufficient to ensure that at the end of a main MTJ etch, an etch front remains in the dielectric layer surrounding the conductive via connections. Thereafter, a MTJ film stack is deposited on the plurality of conductive via connections surrounded by the dielectric layer. The MTJ film stack is etched using an ion beam etch process (IBE), etching through the MTJ film stack and into the dielectric layer surrounding the conductive via connections to form the MTJ devices wherein by etching into the dielectric layer, re-deposition on sidewalls of the MTJ devices is insulating.

Provided is a novel magnetostrictive material that has a high level of magnetostrictive properties without containing rare-earth elements. The magnetostrictive material contains a copper cobalt ferrite that contains a cubic crystal as a primary crystalline phase.

Provided is a novel magnetostrictive material that has a high level of magnetostrictive properties without containing rare-earth elements. The magnetostrictive material contains a copper cobalt ferrite that contains a cubic crystal as a primary crystalline phase.

[Problem] To provide a magnetostrictive material, an energy converter and a method for manufacturing the energy converter, and a vibration power generator, having improved energy efficiency and capable of reducing manufacturing costs.

[Solution] A magnetostrictive material includes a void. A plate-shaped magnetostrictive material includes a through hole in a plate thickness direction. An energy converter is formed by stacking and coupling a plate-shaped magnetostrictive material including a through hole in a plate thickness direction and a plate material in plate thickness direction to each other. The plate-shaped magnetostrictive material is formed of a honeycomb structure including a cell constituting the through hole. A cross sectional shape of the cell in the honeycomb structure is polygonal. The plate material is made of a magnetostrictive material, a soft magnetic material, or a nonmagnetic material. The plate-shaped magnetostrictive material and/or the plate material may be formed of a plurality of pieces, each of which is stacked and coupled in the plate thickness direction.

[Problem] To provide a magnetostrictive material, an energy converter and a method for manufacturing the energy converter, and a vibration power generator, having improved energy efficiency and capable of reducing manufacturing costs.

[Solution] A magnetostrictive material includes a void. A plate-shaped magnetostrictive material includes a through hole in a plate thickness direction. An energy converter is formed by stacking and coupling a plate-shaped magnetostrictive material including a through hole in a plate thickness direction and a plate material in plate thickness direction to each other. The plate-shaped magnetostrictive material is formed of a honeycomb structure including a cell constituting the through hole. A cross sectional shape of the cell in the honeycomb structure is polygonal. The plate material is made of a magnetostrictive material, a soft magnetic material, or a nonmagnetic material. The plate-shaped magnetostrictive material and/or the plate material may be formed of a plurality of pieces, each of which is stacked and coupled in the plate thickness direction.

The magnetostrictive member is formed of a single crystal of an iron-based alloy having magnetostrictive characteristics, is a plate-like body having a long-side direction and a short-side direction, and has a lattice constant of a <100> orientation in the long-side direction not larger than a lattice constant average calculated from lattice constants of <100> orientations in three directions, or the long-side direction, the short-side direction, and a direction orthogonal to the long-side direction and the short-side direction.

The magnetostrictive member is formed of a single crystal of an iron-based alloy having magnetostrictive characteristics, is a plate-like body having a long-side direction and a short-side direction, and has a lattice constant of a <100> orientation in the long-side direction not larger than a lattice constant average calculated from lattice constants of <100> orientations in three directions, or the long-side direction, the short-side direction, and a direction orthogonal to the long-side direction and the short-side direction.