Cornell University

Chi-feng Pai

Daniel C Ralph

Robert A Buhrman

Luqiao Liu

Minh-hai Nguyen

Devices or circuits based on spin torque transfer (STT) and Spin Hall effect are disclosed by using a spin Hall effect (SHE) metal layer coupled to a magnetic free layer for various applications. The efficiency or strength of the STT effect based on this combination of SHE and STT can be enhanced by an interface modification between the SHE metal layer and the magnetic free layer or by modifying or engineering the SHE metal layer by doping the SHE metal with certain impurities or other means.

Circuits and devices based on enhanced spin Hall effect for efficient spin transfer torque

Circuits and devices based on enhanced spin hall effect for efficient spin transfer torque

Three-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including nonvolatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer. The disclosed three-terminal magnetic circuits can also be applied to signal oscillator circuits and other applications.

Electrically gated three-terminal circuits and devices based on spin hall torque effects in magnetic nanostructures apparatus, methods and applications

An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.

Spin hall effect magnetic apparatus, method and applications

3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer. The disclosed 3-terminal magnetic circuits can also be applied to signal oscillator circuits and other applications.

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Ithaca, NY, United States of America

Chi-feng Pai