Wisconsin Alumni Research Foundation

Jiamian Hu

Shihao Zhuang

Chang-Beom Eom

Mingrui Li

Minyi Dai

Optoelectronic transducers that convert a femtosecond (fs)-timescale laser pulse into an a.c. electrical current pulse with an extremely high frequency and a high quality factor (Q) are provided. Both the frequency and amplitude of the a.c. electrical current pulse can be dynamically tuned by the application of a varying bias magnetic field. The optoelectronic transducers are based on a trilayered freestanding membrane that functions as both an acoustic cavity and a magnon cavity. The freestanding membrane includes an electrical conductor layer, a magnetic insulator layer, and a dielectric layer arranged in a vertical stack.

Magnetic-field-tunable terahertz optoelectronic transducer

Acoustically mediated pulsed radiation sources, phased arrays incorporating the radiation sources, and methods of using the radiation sources and phased arrays to generate electromagnetic radiation via magnetic dipole emission are provided. The radiation sources are based on a superlattice heterostructure that supports in-phase magnetic dipole emission from a series of magnetic insulator layers disposed along the length of the heterostructure.

Magnonic electromagnetic radiation sources with high output power at high frequencies

Acoustically mediated spintronic THz emitters based on a stacked, multilayered heterostructure that includes a light-to-acoustic transducer layer, a thermal insulation layer, and a magnetic layer are provided. In the emitters, fast acoustic pulses give rise to long-distance propagation of THz exchange spin waves in a magnetic film. Also provided are THz time-domain spectrometers (THz-TDSs) that incorporate the THz emitters.

Single-mode, high-frequency, high-power narrowband spintronic terahertz emitter

Acoustically mediated spintronic THz emitters in which sound waves, rather than direct laser pulses, give rise to a spin current in a magnetic material via magnetoelastic coupling are provided. The THz emitters include a metal layer that acts as a light-to-acoustic transducer. Also provided are THz time-domain spectrometers (THz-TDSs) that incorporate the THz emitters.

Narrowband, acoustically mediated spintronic terahertz emitter

Spin-orbit torque magnetoresistive random-access memory (SOT-MRAM) cells that undergo perpendicular magnetization switching in the absence of an in-plane magnetic field and methods for their operation are provided. The SOT-MRAM cells use cobalt-iron-boron alloys, cobalt-iron alloys, metallic cobalt, and/or metallic iron as the ferromagnetic free layer in a magnetic tunnel junction. By designing the ferromagnetic layer with appropriate lateral dimensions and operating the SOT-MRAM cells with an appropriate charge current density, deterministic perpendicular magnetization switching is achieved without the need to apply an external in-plane bias collinear with the charge current.

Growing community of inventors

Middleton, WI, United States of America

Jiamian Hu