Abstract: The apparatus and the method for terahertz-based reading of data recorded in the Ruderman-Kittel-Kasuya-Yosida (RKKY)-based magnetic memory provided. The apparatus comprises: a Terahertz Magnon Laser configured to generate THz magnons; wherein the Terahertz Magnon Laser further comprises a Magnon Gain Medium (MGM) configured to support generation of non-equilibrium Terahertz magnons after the electric current is applied across the Terahertz Magnon Laser.

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: A memory cell comprising a first layer of magnetic metal; a Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction spacer coupled to the first layer of magnetic metal; and a second layer of magnetic layer coupled to the RKKY spacer. The effective thickness of the RKKY spacer is changed by applied terahertz radiation resiling in changing the sign of RKKY interaction from a first sign of RKKY interaction to a second sign of RKKY interaction; thus, enabling an RKKY-tunable magnetic memory cell; wherein the first state of the memory corresponds to the first sign of RKKY interaction, and wherein the second state of the memory corresponds to the second sign of RKKY interaction.

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: 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: 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: 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: 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 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: An apparatus for generation of an ultra-high frequency sound waves with frequencies between (1 GHz-10 GHz) is proposed. The apparatus comprises a spin injector, a tunnel junction, a conductive ferromagnetic material including magnon gain medium, a ferromagnetic dielectric material including magnetic phonon-gain medium, and an ultra-high frequency sound waveguide coupled to the ferromagnetic dielectric material. The spin injector is configured to inject minority non-equilibrium elections into the conductive ferromagnetic material via the tunnel junction. The non-equilibrium magnons generated in the magnon gain medium of the conductive ferromagnetic material propagate into the ferromagnetic dielectric material and having the magnon velocity exceeding the sound velocity in the phonon-gain medium of the ferromagnetic dielectric material cause generation of ultra-high frequency non-equilibrium phonons in the ferromagnetic dielectric material.

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.

Abstract: An apparatus for generating ultra-high frequency sound waves with frequencies between (1 GHz-10 GHz) is proposed. The apparatus comprises a magnetic phonon-gain medium configured to generate high frequency non-equilibrium phonons by non-equilibrium magnons having the magnon velocity exceeding the sound velocity in the magnetic phonon-gain medium. The non-equilibrium magnons having the magnon velocity exceeding the sound velocity in the magnetic phonon-gain medium are generated by injected via a tunnel junction non-equilibrium electrons having spin opposite to the direction of magnetization of the magnetic phonon-gain medium.

Abstract: An apparatus for tunable generation of terahertz photons is provided. The apparatus comprises a three level magnon laser, an injection means, a terahertz antenna, and a tuning means. The terahertz antenna further comprises a magnon gain medium that supports generation of nonequilibrium magnons. The magnon gain medium is selected from the group consisting of: a ferromagnetic semiconductor; a dilute magnetic semiconductor (DMS); a half-metallic ferromagnet (HMF); and a ferromagnetic conductor, with a gap in the density of states of the minority electrons around the Fermi energy.

Abstract: An apparatus for generating ultra-high frequency sound waves with frequencies between (1 GHz-10 GHz) is proposed. The apparatus comprises a magnetic phonon-gain medium configured to generate high frequency non-equilibrium phonons by non-equilibrium magnons having the magnon velocity exceeding the sound velocity in the magnetic phonon-gain medium. The non-equilibrium magnons having the magnon velocity exceeding the sound velocity in the magnetic phonon-gain medium are generated by injected non-equilibrium electrons having spin opposite to the direction of magnetization of the magnetic phonon-gain medium. The apparatus further comprises a means for outputting the ultra-high frequency non-equilibrium phonons.