Kabushiki Kaisha Toshiba

National Institute of Advanced Industrial Science and Technology

Tohoku University

Sony Corporation

Japan Science and Technology Agency

Canon Anelva Corporation

Akio Fukushima

Hitoshi Kubota

Shinji Yuasa

Kay Yakushiji

Koji Ando

Hiroaki Yoda

Tadashi Kai

Eiji Kitagawa

Tadaomi Daibou

Taro Nagahama

Minoru Amano

Toshihiko Nagase

Naoharu Shimomura

Katsuya Nishiyama

Makoto Nagamine

Junichi Ito

Shigemi Mizukami

Terunobu Miyazaki

Takayuki Nozaki

Takahide Kubota

Masatoshi Yoshikawa

Masahiko Nakayama

Koji Ueda

Daisuke Saida

Hiroshi Imamura

Yoshishige Suzuki

Shingo Tamaru

Kei Yakushiji

Takahiro Mori

Yutaka Hashimoto

Hiroki Maehara

Takao Ochiai

Yoshinori Nagamine

Kojiro Yagami

Takashi Matsukawa

Atsushi Yamamoto

Masaru Tokou

Ashwin Tulapurkar

Makoto Konoto

The present invention addresses the problem of providing a quantum bit cell and a quantum bit integrated circuit having an easy-to-integrate structure. The quantum bit cell of the present invention including a spin torque oscillator capable of emitting a microwave with a propagation distance of 1 μm or less and having a maximum diameter of 1 μm or less, and a solid-state element quantum bit arranged near the spin torque oscillator at an interval of the propagation distance or less, where a quantum two-level system is controlled by the microwave.

Quantum bit cell and quantum bit integrated circuit

A high-frequency phase-locked oscillation circuit having an extremely narrow peak width and a stable frequency so that a high-frequency wave that is oscillated by the MR element solves a problem of a large peak width of oscillation spectrum. The high-frequency phase-locked oscillation circuit includes a magnetoresistive element that oscillates a high-frequency wave with an oscillating frequency; a reference signal source that outputs a reference signal with a reference frequency; a phase-locked loop circuit having a phase comparator, a loop filter, and a frequency divider; an adder that adds a phase error signal output from the loop filter and a bias voltage for oscillating the high-frequency wave from the magnetoresistive element, and that inputs an added bias voltage to the magnetoresistive element; and a filter provided between the frequency divider and the magnetoresistive element.

High-frequency phase-locked oscillation circuit

A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.

Magnetic memory

According to one embodiment, a magnetoresistive element includes a first magnetic layer having a variable magnetization direction; a second magnetic layer having an invariable magnetization direction; and a tunnel barrier layer provided between the first magnetic layer and the second magnetic layer and including an MgFeO film, wherein the MgFeO film contains at least one element selected from a group consisting of Ti, V, Mn, and Cu.

Magnetoresistive element and magnetic memory

A magnetoresistive element according to an embodiment includes: a base layer; a first magnetic layer formed on the base layer, and including a first magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the first magnetic film including MnGa(45&#x2266;x&#x3c;64 atomic %); a first nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the first nonmagnetic layer, and including a second magnetic film having an axis of easy magnetization in a direction perpendicular to a film plane, the second magnetic film including MnGa(45&#x2266;y&#x3c;64 atomic %). The first and second magnetic layers include different Mn composition rates from each other, a magnetization direction of the first magnetic layer is changeable by a current flowing between the first magnetic layer and the second magnetic layer via the first nonmagnetic layer.

A magnetoresistive element according to an embodiment includes: a first and second magnetic layers having an easy axis of magnetization in a direction perpendicular to a film plane; and a first nonmagnetic layer interposed between the first and second magnetic layers, at least one of the first and second magnetic layers including a structure formed by stacking a first and second magnetic films, the second magnetic film being located closer to the first nonmagnetic layer, the second magnetic film including a structure formed by repeating stacking of a magnetic material layer and a nonmagnetic material layer at least twice, the nonmagnetic material layers of the second magnetic film containing at least one element selected from the group consisting of Ta, W, Hf, Zr, Nb, Mo, Ti, V, and Cr, one of the first and second magnetic layers having a magnetization direction that is changed by applying a current.

A random number generating device is constructed such that it has improved random number generation rate and allows for construction of compact circuit with ease. The random number generating device includes a magnetoresistive element that has three layers consisting of a magnetization free layer, an interlayer, and a magnetization fixed layer, and has at least two resistance values depending on arrangement of magnetization in the magnetization free layer and the magnetization fixed layer, wherein the magnetoresistive element is subjected to be applied with a magnetization current so that the inversion probability of the magnetization free layer assumes a value between 0 and 1, through which the resistance value of the magnetoresistive element is extracted as random numbers.

Random number generating device

According to one embodiment, a magnetoresistive effect element includes a first magnetic layer including perpendicular anisotropy to a film surface and an invariable magnetization direction, the first magnetic layer having a magnetic film including an element selected from a first group including Tb, Gd, and Dy and an element selected from a second group including Co and Fe, a second magnetic layer including perpendicular magnetic anisotropy to the film surface and a variable magnetization direction, and a nonmagnetic layer between the first magnetic layer and the second magnetic layer. The magnetic film includes amorphous phases and crystals whose particle sizes are 0.5 nm or more.

Magnetoresistive effect element, magnetic memory

According to one embodiment, a magnetoresistive element includes a first magnetic layer with a variable magnetization and an easy-axis in a perpendicular direction to a film surface, a second magnetic layer with an invariable magnetization and an easy-axis in the perpendicular direction, and a first nonmagnetic layer between the first and second magnetic layers. The first magnetic layer comprises a ferromagnetic material including an alloy in which Co and Pd, or Co and Pt are alternately laminated on an atomically close-packed plane thereof. The first magnetic layer has C-axis directing the perpendicular direction. And a magnetization direction of the first magnetic layer is changed by a current flowing through the first magnetic layer, the first nonmagnetic layer and the second magnetic layer.

A magneto-resistive device has a magnetic free layer (), a magnetic pinned layer () having a magnetic moment larger than that of the magnetic free layer, and an intermediate layer () provided between the magnetic free layer and the magnetic pinned layer. The negative-resistance device is characterized in that the negative-resistance device shows negative resistance by making the magnetic free layer continually change the magnetization direction along with the increase of the voltage which is applied to a magneto-resistive device so that electrons flow into the negative-resistance device from a magnetic free layer side.

Negative-resistance device with the use of magneto-resistive effect

A strip line integrated microwave generating element and a microwave detecting element comprises a signal electrode and a ground electrode. The element has a magnetic tunnel junction structure which includes a magnetization fixed layer, a MgO tunnel barrier layer, and a magnetization free layer. The magnetization free layer is 200 nm square or smaller in a cross-sectional area. The magnetization fixed layer is in contact with either one of the signal electrode and the ground electrode while the magnetization free layer of the element being in contact with the other. The element is smaller than the electrodes and mounted on a part of the signal electrode or the ground electrode. A MR ratio of the element is of 100% or more. A resistance value of the element is from 50&#x3a9; to 300&#x3a9;. The resistance of the element is matched with an impedance of the microwave transmission line.

Microwave transmission line integrated microwave generating element and microwave transmission line integrated microwave detecting element

Growing community of inventors

Tsukuba, Japan

Akio Fukushima