Agency for Science, Technology and Research

National University of Singapore

Hitachi Global Storage Technologies Netherlands B.v.

Chartered Semiconductor Manufacturing Ltd (corporation)

Data Storage Institute

Yihong Wu

Yuankai Zheng

Lap Chan

Jinshan Li

Wen-yaung Lee

Ganesh S Samudra

Andrew Khoh

Kebin Li

Byong-Il Choi

Yumeng Yang

Hang Xie

Dan You

Yanjun Xu

Xiaoyan Wang

A method for detecting a magnetic field using a spin-orbit torque magnetic field sensor is described. The spin-orbit torque magnetic field sensor comprises a magnetic layer having a switchable magnetic state. The method comprises: (i) providing an alternating current to the sensor for creating an oscillatory spin-orbit torque in the magnetic layer to switch the switchable magnetic state between two magnetic states; and (ii) measuring an output voltage of the sensor, the output voltage being dependent on the magnetic field and is a time average of a time-varying anomalous Hall voltage generated in the magnetic layer in response to the oscillatory spin-orbit torque and the magnetic field. The time-varying anomalous Hall voltage is a function of the alternating current and a Hall resistance of the magnetic layer, and the Hall resistance is associated with a duration in which the switchable magnetization is in each of the two magnetic states and the duration is associated with a magnitude and a polarity of the magnetic field. An apparatus for performing the method is also described.

Method and an apparatus for detecting a magnetic field

A magnetic system containing a plurality of stacked layer arrays, each of which includes a first anti-ferromagnetic (AFM1) layer, a heavy metal (HM) layer formed of a material having strong spin-orbit coupling, and, optionally, a ferromagnetic (FM) layer or a second anti-ferromagnetic (AFM2) layer. Also disclosed is a method of preparing such a magnetic system.

Antiferromagnet and heavy metal multilayer magnetic systems for switching magnetization using spin-orbit torque

A memory cell for a magnetic memory device comprising a first hard magnetic later having a first fixed magnetization vector; a second hard magnetic later having a second fixed magnetization vector; a first soft magnetic layer having a first alterable magnetization vector and disposed adjacent to the first hard magnetic layer and a second soft magnetic layer having a second alterable magnetization vector and disposed adjacent to the second hard magnetic layer, the first and the second soft magnetic layers are magnetostatically coupled antiparallel to each other to form a flux-closed structure. An electrically conductive layer is disposed between the two soft magnetic layers for passing an electric current therethrough to perform the read and write operations. A magnetic memory device made thereof possesses a higher thermal stability against external thermal fluctuations and in the meantime has a lower power dissipation in writing operations.

Magnetic memory device

A magnetic head and magnetic storage system containing such a head, the head including a free layer and a layer of metal oxide substantially epitaxially formed relative to the free layer. Preferably, the layer of metal oxide is a crystalline structure, and is of ZnO.

Epitaxial oxide cap layers for enhancing GMR performance

A magnetic memory device includes a plurality of transistors () formed on a substrate and a common magnetic memory block () including a multiple effective magnetoresistive elements (), a ferromagnetic recording (), a non-magnetic space (), and a free magnetic reading () layer formed above the transistors (). An extended common digital line () is located above a common magnetic memory block () which is electrically connected with a respective source/drain electrode of the transistors () through each a contact at a respective active area. The specific magnetization state of the ferromagnetic recording layer at the active areas can be changed by a heating process and applying an external field induced from the common digital line (), the bit () or word () lines. The change in resistance of the effective magnetoresistive element () can be detected by means of changing the magnetization state of the free magnetic reacting layer during reading, thus a smaller switching field is required.

Nano-contacted magnetic memory device

A trial semiconductor photomask design having discontinuity points is provided, and each of the discontinuity points is treated as simulated light sources. Simulated light from each of the simulated light sources is focused, and a composite image intensity of the focused simulated light is calculated to verify the trial semiconductor photomask design. The trial semiconductor photomask design is sharpened. A photomask design specification is generated for use in fabricating such a photomask.

System and method for designing semiconductor photomasks

A memory cell () for a magnetic memory device () includes a free layer (), a cap layer, an antiferromagnetic layer, and a synthetic antiferromagnetic layer which comprises two or more than two ferromagnetic layers that are antiferromagnetically coupled through non-magnetic space layers. The synthetic antiferromagnetic layer is pinned by antiferromagnetic layer. The antiferromagnetic layer and the synthetic antiferromagnetic layer form a synthetic antiferromagnetic pinned (SAFP) recording layer. The magnetization of the SAFP recording layer can be changed by combining a heating process and an external field induced from currents flowing along the bit line () and the word line (). Therefore, a MRAM with high density, high thermal stability, low power dissipation and high heat tolerance can be achieved after introducing the SAFP recording layer due to the high volume and anisotropy energy of the SAFP recording layer.

A circuit for controlling a read operation for a magnetic random access memory (MRAM) comprising an array of magnetic tunnel junctions (MTJ) having conducting row and column lines attached thereto. The circuitry comprises a current supply for providing a read current, and a row selector for selecting a row containing a junction to be read and applying the read current to that row with the respective row line. An unselected row switch switches to at least some of the row lines not connected to the MTJ to be read, and a voltage source applies, via the unselected row switch, a voltage to each of the unselected row lines that is substantially identical in level to the voltage on the selected row line. A column selector selects the column line connected to the array containing the MTJ to be read, and a voltage detector for detecting the voltage across the MTJ to be read via the selected column and row lines.

Growing community of inventors

Singapore, Singapore

Yihong Wu