Abstract: Provided is a magnetic nanoparticle heating method using resonance, the method including (a) providing magnetic nanoparticles, (b) applying a direct current (DC) magnetic field to the magnetic nanoparticles, and (c) applying an alternating current (AC) magnetic field to the magnetic nanoparticles 100, wherein a temperature change rate dT/dt of the magnetic nanoparticles is increased to at least 10 K/s or more by adjusting at least one of a strength of the DC magnetic field, a frequency of the AC magnetic field, a strength of the AC magnetic field, and a pulse width of the AC magnetic field.

Abstract: A core magnetization reversal method includes transforming the first magnetic skyrmion into a skyrmionium by applying a first alternating current (AC) magnetic field to the first magnetic skyrmion, and then transforming the skyrmionium into a second magnetic skyrmion by applying a second AC magnetic field to the skyrmionium. The first magnetic skyrmion may be formed on a hemispherical shell, which may be formed by (i) preparing a membrane having a plurality of protrusions, and (ii) stacking, on the membrane, a first layer including at least one of platinum (Pt), nickel (Ni), and palladium (Pd), and a second layer including a ferromagnetic material. The first and second AC magnetic fields may have different frequencies.

Abstract: A signal transferring device includes a first structure that includes a first magnetic thin film structure having a first magnetic vortex configured to receive a signal as an input signal, a second structure that is spaced apart from at least one side of the first structure, the second structure including a second magnetic thin film structure having a second magnetic vortex configured to transfer the signal, and a third structure that is spaced apart from at least one side of the second structure, the third structure including a third magnetic thin film structure having a third magnetic vortex configured to output the signal from the signal transferring device. The first and third structures have a symmetrical shape and the second structure has an asymmetrical shape.

Abstract: Provided is a method of selective activation for a magnetic nanoparticle having a magnetic vortex structure. The method of selective activation for a magnetic nanoparticle in accordance with an embodiment of the present disclosure includes providing a magnetic nanoparticle having a magnetic vortex structure; applying a first magnetic field to the magnetic nanoparticle so that the magnetic nanoparticle has a resonance frequency; and activating the magnetic nanoparticle by applying a second magnetic field having the resonance frequency to the magnetic nanoparticle.

Abstract: Provided is a method of selective activation for a magnetic nanoparticle having a magnetic vortex structure. The method of selective activation for a magnetic nanoparticle in accordance with an embodiment of the present disclosure includes providing a magnetic nanoparticle having a magnetic vortex structure; applying a first magnetic field to the magnetic nanoparticle so that the magnetic nanoparticle has a resonance frequency; and activating the magnetic nanoparticle by applying a second magnetic field having the resonance frequency to the magnetic nanoparticle.

Abstract: There is provided a magnonic-crystal spin wave device capable of controlling a frequency of a spin wave. The magnonic-crystal spin wave device according to the invention includes a spin wave waveguide made of magnetic material, and the spin wave waveguide guides the spin wave so as to propagate in one direction, and includes a magnonic crystal part which has a cross-section orthogonal to the direction, and at least one of a shape, area size, and center line of the cross-section periodically changes in the direction. In accordance with the invention, it is possible to easily control the frequency of the spin wave using the spin wave waveguide made of single magnetic material.

Abstract: Provided are an ultrafast magnetic recording element and a nonvolatile magnetic random access memory using the same. The magnetic recording element includes a read electrode, a magnetic pinned layer formed on the read electrode, and an insulating layer or a conductive layer formed on the magnetic pinned layer. The magnetic recording element includes a magnetic free layer formed on the insulating layer or the conductive layer, in which a magnetic vortex is formed, and a plurality of drive electrodes applying a current or magnetic field to the magnetic free layer. According to the magnetic recording elements, the magnetic recording element with a simple structure can be realized using a magnetic layer with a magnetic vortex formed, and the magnetic recording element can be accurately driven with low power using a plurality of drive electrodes.

Abstract: Provided are a method for recording information in a magnetic recording element and a method for recording information in a magnetic random access memory. The method for recording information in a magnetic recording element includes preparing the magnetic recording element having a magnetic free layer in which a magnetic vortex is formed. A current or a magnetic field whose direction varies with time is applied to the magnetic free layer to switch a core orientation of a magnetic vortex formed in the magnetic free layer to an upward direction or downward direction from a top surface of the magnetic free layer “0” or “1” is assigned according to the direction of the core orientation of the magnetic vortex formed in the magnetic free layer.

Abstract: Provided are a method of generating strong spin waves, a method of simultaneously generating spin waves and electromagnetic waves, a logic operation device using spin waves, a variety of spin wave devices employing the same, and a method of controlling phases of spin waves. In the method of generating spin waves, strong spin waves are generated by supplying various shapes of energies to a magnetic material in which a magnetic vortex and magnetic antivortex spin structures exist separately or together. In the logic operation device, wave factors of frequency, wavelength, amplitude, and phase of a spin wave generated by the method of generating spin waves are controlled and wave characteristics such as reflection, refraction, transmission, tunneling, superposition, interference, and diffraction are used.

Abstract: Provided are a method for read-out of information in a magnetic recording element and a method for read-out of information in a magnetic random access memory. In the method, a magnetic recording element including a magnetic free layer where a magnetic vortex is formed is prepared, and “0” or “1” is assigned according to a core orientation of a magnetic vortex formed in the magnetic free layer. The magnetic vortex core formed in the magnetic free layer rotates on the magnetic free layer by applying a current or magnetic field, of which a direction varies with time, to the magnetic free layer with the magnetic vortex formed. “0” or “1” assigned according to the core orientation of the magnetic vortex formed in the magnetic free layer is read out by measuring a characteristic caused by a difference in a rotation radius of the magnetic vortex core.

Abstract: There is provided a magnonic-crystal spin wave device capable of controlling a frequency of a spin wave. The magnonic-crystal spin wave device according to the invention includes a spin wave waveguide made of magnetic material, and the spin wave waveguide guides the spin wave so as to propagate in one direction, and includes a magnonic crystal part which has a cross-section orthogonal to the direction, and at least one of a shape, area size, and center line of the cross-section periodically changes in the direction. In accordance with the invention, it is possible to easily control the frequency of the spin wave using the spin wave waveguide made of single magnetic material.

Abstract: Provided are a method for recording information in a magnetic recording element and a method for recording information in a magnetic random access memory. The method for recording information in a magnetic recording element includes preparing the magnetic recording element having a magnetic free layer in which a magnetic vortex is formed. A current or a magnetic field whose direction varies with time is applied to the magnetic free layer to switch a core orientation of a magnetic vortex formed in the magnetic free layer to an upward direction or downward direction from a top surface of the magnetic free layer “0” or “1” is assigned according to the direction of the core orientation of the magnetic vortex formed in the magnetic free layer.

Abstract: Provided are a method for read-out of information in a magnetic recording element and a method for read-out of information in a magnetic random access memory. In the method, a magnetic recording element including a magnetic free layer where a magnetic vortex is formed is prepared, and “0” or “1” is assigned according to a core orientation of a magnetic vortex formed in the magnetic free layer. The magnetic vortex core formed in the magnetic free layer rotates on the magnetic free layer by applying a current or magnetic field, of which a direction varies with time, to the magnetic free layer with the magnetic vortex formed. “0” or “1” assigned according to the core orientation of the magnetic vortex formed in the magnetic free layer is read out by measuring a characteristic caused by a difference in a rotation radius of the magnetic vortex core.

Abstract: Provided are an ultrafast magnetic recording element and a nonvolatile magnetic random access memory using the same. The magnetic recording element includes a read electrode, a magnetic pinned layer formed on the read electrode, and an insulating layer or a conductive layer formed on the magnetic pinned layer. The magnetic recording element includes a magnetic free layer formed on the insulating layer or the conductive layer, in which a magnetic vortex is formed, and a plurality of drive electrodes applying a current or magnetic field to the magnetic free layer. Alternatively, the magnetic recording element includes a magnetic free layer in which a magnetic vortex is formed, a plurality of drive electrodes applying a current or a magnetic field to the magnetic free layer, and a read line disposed around the magnetic free layer. Herein, a current generated by a voltage induced by the movement of a magnetic vortex core flows through the read line.

Abstract: Provided are a method of generating strong spin waves, a method of simultaneously generating spin waves and electromagnetic waves, a logic operation device using spin waves, a variety of spin wave devices employing the same, and a method of controlling phases of spin waves. In the method of generating spin waves, strong spin waves are generated by supplying various shapes of energies to a magnetic material in which a magnetic vortex and magnetic antivortex spin structures exist separately or together. When energies are applied to a patterned magnetic material so that magnetic vortex or magnetic antivortex can be generated, a strong torque is generated in a vortex core so that strong spin waves can be generated from the vortex core. The spin waves generated in this way have large amplitudes, short wavelengths, and high frequencies.

Abstract: A method of controlling a magnetization easy axis of a ferromagnetic film, an ultrahigh-density, low power, nonvolatile magnetic memory using the control method, and a method of writing information on the magnetic memory. The method includes the step of arranging an electrode layer, a piezoelectric layer and a magnetic layer in a layered structure. Voltage is applied to the electrode layer to generate an electric field. Thereafter, lattice change is caused in the piezoelectric layer using the generated electric field. A magnetization easy axis of the magnetic layer is reversibly switched between in-plane and out-of-plane by exerting stress generated by the lattice change onto the magnetic layer.

Abstract: Disclosed herein are a method of controlling a magnetization easy axis of a ferromagnetic film, an ultrahigh-density, low power, nonvolatile magnetic memory using the control method, and a method of writing information on the magnetic memory. The method includes the step of arranging an electrode layer, a piezoelectric layer and a magnetic layer in a layered structure. Thereafter, voltage is applied to the electrode layer to generate an electric field. Thereafter, lattice change is caused in the piezoelectric layer using the generated electric field. Finally, a magnetization easy axis of the magnetic layer is reversibly switched between in-plane and out-of-plane by exerting stress generated by the lattice change onto the magnetic layer.