Abstract: An apparatus for generation of tunable terahertz radiation is provided. The apparatus comprises: a plurality of terahertz magnon laser generators, whereas at least one such terahertz magnon laser generator comprises a multilayer column, and a terahertz transparent medium separating at least two such terahertz magnon laser generators. At least one such multilayer column further comprises: a substrate, a bottom electrode coupled with the substrate, a bottom layer coupled with the bottom electrode, a tunnel junction coupled with the bottom layer, a top layer coupled with the tunnel junction, a pinning layer coupled with the spin injector, and a top electrode coupled with the pinning layer.

Abstract: A method for tuning the frequency of THz radiation is provided. The method utilizes an apparatus comprising a spin injector, a tunnel junction coupled to the spin injector, and a ferromagnetic material coupled to the tunnel junction. The ferromagnetic material comprises a Magnon Gain Medium (MGM). The method comprises the step of applying a bias voltage to shift a Fermi level of the spin injector with respect to the Fermi level of the ferromagnetic material to initiate generation of non-equilibrium magnons by injecting minority electrons into the Magnon Gain Medium. The method further comprises the step of tuning a frequency of the generated THz radiation by changing the value of the bias voltage.

Abstract: An apparatus for novel technique of high-speed magnetic recording based on manipulating pinning layer in magnetic tunnel junction-based memory by using terahertz magnon laser is provided. The apparatus comprises a terahertz writing head configured to generate a tunable terahertz writing signal and a memory cell including a spacer that comprises a thickness configured based on Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. The memory cell comprises two separate memory states: a first binary state and a second binary state; wherein the first binary memory state corresponds to a ferromagnetic sign of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction corresponding to a first thickness value of the spacer; and wherein the second binary memory state corresponds to an antiferromagnetic sign of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction corresponding to a second thickness value of the spacer. The thickness of the spacer is manipulated by the tunable terahertz writing signal.

Abstract: An apparatus for generation of coherent terahertz radiation is provided. In one example, the apparatus includes one or more multilayer tunable microcolumns. In turn, a multilayer tunable microcolumn can include a substrate, a bottom electrode, a bottom layer of a ferromagnetic material further comprising a magnon gain medium (MGM) coupled to the bottom electrode, a tunnel junction coupled to the ferromagnetic material, a spin injector coupled to the tunnel junction, a pinning layer coupled to the spin injector, a reference layer coupled to the pinning layer and a top electrode. In one example, a containment cavity encloses at least one of the multilayer tunable microcolumns. In one example, a storage cavity encloses the containment cavity.

Abstract: A method for tuning the frequency of THz radiation is provided. The method utilizes an apparatus comprising a spin injector, a tunnel junction coupled to the spin injector, and a ferromagnetic material coupled to the tunnel junction. The ferromagnetic material comprises a Magnon Gain Medium (MGM). The method comprises the step of applying a bias voltage to shift a Fermi level of the spin injector with respect to the Fermi level of the ferromagnetic material to initiate generation of non-equilibrium magnons by injecting minority electrons into the Magnon Gain Medium. The method further comprises the step of tuning a frequency of the generated THz radiation by changing the value of the bias voltage.

Abstract: An apparatus for generation of tunable terahertz radiation is provided. The apparatus comprises: a plurality of terahertz magnon laser generators, whereas at least one such terahertz magnon laser generator comprises a multilayer column, and a terahertz transparent medium separating at least two such terahertz magnon laser generators. At least one such multilayer column further comprises: a substrate, a bottom electrode coupled with the substrate, a bottom layer coupled with the bottom electrode, a tunnel junction coupled with the bottom layer, a top layer coupled with the tunnel junction, a pinning layer coupled with the spin injector, and a top electrode coupled with the pinning layer.

Abstract: An apparatus for novel technique of high-speed magnetic recording based on manipulating pinning layer in magnetic tunnel junction-based memory by using terahertz magnon laser is provided. The apparatus comprises a terahertz writing head configured to generate a tunable terahertz writing signal and a memory cell including a spacer that comprises a thickness configured based on Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. The memory cell comprises two separate memory states: a first binary state and a second binary state; wherein the first binary memory state corresponds to a ferromagnetic sign of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction corresponding to a first thickness value of the spacer; and wherein the second binary memory state corresponds to an antiferromagnetic sign of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction corresponding to a second thickness value of the spacer. The thickness of the spacer is manipulated by the tunable terahertz writing signal.

Abstract: An apparatus comprising a ferromagnetic conductive material including a magnon gain medium (MGM) and a tunnel junction coupled to the ferromagnetic conductive material are provided. The magnon gain medium (MGM) further comprises a conduction band that is split into two sub bands separated by an exchange energy gap, a first sub band having spin up, and a second sub band having spin down. The applied bias voltage is configured to shift the Fermi level of the external metallic contact with respect to the Fermi level of the ferromagnetic conductive material so that the injected electrons are configured to tunnel into the second sub band having spin down.