One aspect of the disclosure provides a power receiver configured to wirelessly transfer power from at least one power transmitter. The power receiver comprises a plurality of magnetic oscillators, each magnetic oscillator of the plurality of magnetic oscillators having a mechanical resonant frequency substantially equal to a first frequency, the plurality of magnetic oscillators configured to generate a first time-varying magnetic field in response to exposure to a second time-varying magnetic field. The power receiver further comprises at least one current circuit configured to generate a time-varying electric current in response to exposure to the first time-varying magnetic field. The first time-varying magnetic field has an operating frequency substantially equal to the first frequency.

Described is an oscillating apparatus which comprises: an interconnect with spin-coupling material (e.g., Spin Hall Effect (SHE) material); and a magnetic stack having two magnetic layers such that one of the magnetic layers is coupled to the interconnect, wherein each of the two magnetic layers have respective magnetization directions to cause the magnetic stack to oscillate.

A spin-torque oscillator includes: a driving reference layer having a fixed magnetization; a nonmagnetic spacer layer; and a free layer having a changeable magnetization exhibiting an easy-cone magnetic anisotropy, the nonmagnetic spacer layer being between the driving reference layer and the free layer, a magnetic anisotropy energy of the free layer having a local maximum along an axis, a local minimum at an angle from the axis, and a global maximum different from the local maximum, the angle being greater than zero degrees, wherein the spin-torque oscillator is configured such that the changeable magnetization of the free layer precesses around the axis.

A device including a spin channel to transport a spin current, a nano-oscillator, and a magnetoresistive device that receives the spin current from the nano-oscillator. The nano-oscillator includes a magnetization state that oscillates between a first state and a second state in response to an input voltage or current. The oscillation of the nano-oscillator may induce the spin current within the spin channel. The magnetoresistive device includes a magnetization state that is set based at least in part on the received spin current.

An apparatus includes a polarizer of a spin-torque oscillator (STO). The polarizer has a perpendicular magnetic anisotropy (PMA) and is configured to receive a first signal having a current density of between 0.5110.sup.6 amps per square centimeter (amps/cm.sup.2) and 15.310.sup.6 amps/cm.sup.2. The apparatus also includes a magnetically soft oscillating region including an antiferromagnetic (AF) coupling layer coupling a first free layer to a second free layer and located between the polarizer and a reference region. The reference region is configured to output a second signal responsive to the first signal, the second signal having a frequency less than 8 gigahertz (GHz).

A spintronic wireless communication system for simultaneously modulating multiband frequencies and amplitudes includes a plurality of spin-torque transfer devices which have different frequency characteristics from each other, and OOK modulate or multi-level ASK modulate input data to thereby output a multiband OOK modulation signal or a multiband, multi-level ASK modulation signal; a plurality of matching networks which match individual impedances of the plurality of spin-torque transfer devices; and a broadband antenna which receives the multiband OOK modulation signal or the multiband, multi-level ASK modulation signal from ends of the plurality of matching networks and simultaneously transmits the signals to the outside.

A power transmitter is configured to wirelessly transfer power to at least one power receiver. The power transmitter includes at least one excitation circuit configured to generate a time-varying first magnetic field in response to a time-varying electric current flowing through the at least one excitation circuit. The time-varying first magnetic field has an excitation frequency. The power transmitter further includes a plurality of magnetic oscillators. Each magnetic oscillator of the plurality of magnetic oscillators has a mechanical resonant frequency substantially equal to the excitation frequency. The plurality of magnetic oscillators is configured to generate a time-varying second magnetic field in response to the first magnetic field.

A magnetoresistive effect oscillator is provided which can realize a rise or a fall of oscillation at a higher speed. In the magnetoresistive effect oscillator, at the rise, a current having a first current density, which is larger than a critical current density for oscillation, is applied, and thereafter a current having a second current density, which is less than the current density corresponding to the first current density and not less than the critical current density for oscillation, is applied such that the magnetoresistive effect element oscillates at a predetermined frequency. In the magnetoresistive effect oscillator, at the fall, starting from the state where a first current density is applied to hold the magnetoresistive effect element in an oscillating condition, a current having a second current density and having polarity reversed to that of the first current density is applied such that the oscillation disappears.

An apparatus includes a polarizer, a first free layer, a second free layer, and an antiferromagnetic (AF) coupling layer. The polarizer has a perpendicular magnetic anisotropy (PMA). The polarizer, the first free layer, the second free layer, and the AF coupling layer are included in a spin-torque oscillator (STO). The AF coupling layer is positioned between the first free layer and the second free layer.

Techniques, systems, and devices are disclosed for implementing a quasi-linear spin-torque nano-oscillator based on exertion of a spin-transfer torque on the local magnetic moments in the magnetic layer and precession of the magnetic moments in the magnetic layer within a spin valve. Examples of spin-torque nano-oscillators (STNOs) are disclosed to use spin polarized currents to excite nano magnets that undergo persistent oscillations at RF or microwave frequencies. The spin currents are applied in a non-uniform manner to both excite the nano magnets into oscillations and generate dynamic damping at large amplitude as a feedback to reduce the nonlinearity associated with mixing amplitude and phase fluctuations.