A permanent magnet includes at least two antiferromagnetic layers and at least two first ferromagnetic layers. A magnetization direction of each first ferromagnetic layer is set, by an exchange coupling, with one of the antiferromagnetic layers of the stack, parallel to and in the same direction as the magnetization directions of the other first ferromagnetic layers. The permanent magnet also includes at least one second ferromagnetic layer. A magnetization direction of each second ferromagnetic layer is pinned only by RKKY (Ruderman-Kittel-Kasuya-Yosida) coupling with at least one of the first ferromagnetic layers or with at least one other of the second ferromagnetic layers.

A variable-frequency magnetoresistive effect element includes a magnetoresistive effect element, a magnetic-field applying mechanism that applies a magnetic field to the magnetoresistive effect element, an electric-field applying mechanism that applies an electric field to the magnetoresistive effect element, and a control terminal connected to the electric-field applying mechanism and used for applying a voltage that varies in at least one of magnitude and polarity to the electric-field applying mechanism. The magnetoresistive effect element contains an antiferromagnetic material or ferrimagnetic material having a magnetoelectric effect. A spin torque oscillation frequency or spin torque resonance frequency of the magnetoresistive effect element is controlled by varying the voltage applied via the control terminal in at least one of magnitude and polarity.

A spin current magnetization rotational element includes: a spin-orbit torque wiring extending in a first direction; and a first ferromagnetic layer laminated in a second direction intersecting with the spin-orbit torque wiring, wherein the first ferromagnetic layer comprises a plurality of ferromagnetic constituent layers and at least one inserted layer sandwiched between adjacent ferromagnetic constituent layers, and polarities of spin Hall angles of two layers, which sandwich at least one of the ferromagnetic constituent layers among the plurality of the ferromagnetic constituent layers, differ.

Embodiments of the present invention relate generally to logic devices, and more particularly, to magnetoelectric magnetic tunneling junction computational devices. Aspects of the disclosed technology include a stand-alone voltage-controlled magnetoelectric device that satisfies essential requirements for general logic applications, including nonlinearity, gain, concatenability, feedback prevention, and a complete set of Boolean operations based on the majority gate and inverter. Aspects of the present disclosed technology can eliminate the need for any auxiliary FETs to preset or complicated clocking schemes and prevents the racing condition.

Embodiments of the present invention relate generally to logic devices, and more particularly, to magnetoelectric magnetic tunneling junction computational devices. Aspects of the disclosed technology include a stand-alone voltage-controlled magnetoelectric device that satisfies essential requirements for general logic applications, including nonlinearity, gain, concatenability, feedback prevention, and a complete set of Boolean operations based on the majority gate and inverter. Aspects of the present disclosed technology can eliminate the need for any auxiliary FETs to preset or complicated clocking schemes and prevents the racing condition.

Memory cells are disclosed. Magnetic regions within the memory cells include an alternating structure of magnetic sub-regions and coupler sub-regions. The coupler material of the coupler sub-regions antiferromagnetically couples neighboring magnetic sub-regions and effects or encourages a vertical magnetic orientation exhibited by the neighboring magnetic sub-regions. Neighboring magnetic sub-regions, spaced from one another by a coupler sub-region, exhibit oppositely directed magnetic orientations. The magnetic and coupler sub-regions may each be of a thickness tailored to form the magnetic region in a compact structure. Interference between magnetic dipole fields emitted from the magnetic region on switching of a free region in the memory cell may be reduced or eliminated. Also disclosed are semiconductor device structures, spin torque transfer magnetic random-access memory (STT-MRAM) systems, and methods of fabrication.

Method for producing an integrated magnetic device with variable inductance, comprising: a) making of a piezoelectric element on a first substrate; b) making of a first electrically conductive element on a face of the piezoelectric element, and fastening of the ends of the piezoelectric element to a second substrate such that the piezoelectric element is arranged facing a cavity formed between the second substrate and the piezoelectric element, the first electrically conductive element being arranged in and/or against the second substrate or against the piezoelectric element; c) removing of the first substrate; d) making of a second electrically conductive element on another face of the piezoelectric element; and further comprising the making of an electrical and/or magnetic coupling of the first and second electrically conductive elements, and the making of a magnetic element arranged against and/or in the piezoelectric element and between the electrically conductive elements.

Memory cells are disclosed. Magnetic regions within the memory cells include an alternating structure of magnetic sub-regions and coupler sub-regions. The coupler material of the coupler sub-regions antiferromagnetically couples neighboring magnetic sub-regions and effects or encourages a vertical magnetic orientation exhibited by the neighboring magnetic sub-regions. Neighboring magnetic sub-regions, spaced from one another by a coupler sub-region, exhibit oppositely directed magnetic orientations. The magnetic and coupler sub-regions may each be of a thickness tailored to form the magnetic region in a compact structure. Interference between magnetic dipole fields emitted from the magnetic region on switching of a free region in the memory cell may be reduced or eliminated. Also disclosed are semiconductor device structures, spin torque transfer magnetic random-access memory (STT-MRAM) systems, and methods of fabrication.

Magneto-impedance (MI) sensors employing current confinement and exchange bias layer(s) for increased MI sensitivity are disclosed. MI sensors may be used as biosensors to detect biological materials. The sensing by the MI devices is based on a giant magneto-impedance (GMI) effect, which is very sensitive to a magnetic field. The GMI effect is a change in impedance of a magnetic material resulting from a change in skin depth of the magnetic material as a function of an external direct current (DC) magnetic field applied to the magnetic material and an alternating current (AC) current flowing through the magnetic material (or adjacent conductive materials). Thus, this change in impedance resulting from a magnetic stray field generated by magnetic nanoparticles can be detected in lower concentrations and measured to determine the amount of magnetic nanoparticles present, and thus the target analyte of interest.

Embodiments of the present invention relate generally to logic devices, and more particularly, to magnetoelectric magnetic tunneling junction computational devices. Aspects of the disclosed technology include a stand-alone voltage-controlled magnetoelectric device that satisfies essential requirements for general logic applications, including nonlinearity, gain, concatenability, feedback prevention, and a complete set of Boolean operations based on the majority gate and inverter. Aspects of the present disclosed technology can eliminate the need for any auxiliary FETs to preset or complicated clocking schemes and prevents the racing condition.