Carnegie Mellon University

Iron City Integrated Circuits

David M Bromberg

Lawrence Thomas Pileggi

Jian-Gang Zhu

Matthew Moneck

Huseyin E Sumbul

Jiam-Gang (Jimmy) Zhu

Vincent Sokalski

Daniel H Morris

This disclosure relates to a memory device that includes at least one magnetic track on a substrate, wherein the at least one magnetic track comprises one or more magnetic domains. Contacts can be disposed on the at least one magnetic track according to a predetermined arrangement to form a plurality of bitcells on the at least one magnetic track, wherein each one of the plurality of bitcells is configured to store at least one magnetic domain. The device can include a timing circuit connected to the contacts, with the timing circuit being configured to apply to the contacts multiple phases of electric currents according to a predetermined timing sequence to cause the at least one magnetic domain to shift from the each one of the plurality of bitcells to an adjacent one of the plurality of bitcells on the at least one magnetic track.

Magnetic shift register

A method includes receiving a data bit value at a buffer in a bitcell based on a first state of a write bitline connected to the buffer, and transferring the data bit value from the buffer to a first magnetic switching cell in the bitcell for a later read operation at least by holding the write bitline to a reference value different from the first state, and asserting first and second predetermined voltage levels on respective first and second write wordlines connected to the buffer.

Bitcell wth magnetic switching elements

In one aspect, a nonvolatile magnetic logic device comprises an electrically insulating layer, a write path, and a read path. The write path comprises a plurality of write path terminals and a magnetic layer having a uniform magnetization direction that is indicative of a direction of magnetization of the magnetic layer in a steady state. A logic state is written to the nonvolatile magnetic logic device by passing a current through the plurality of write path terminals. The read path comprises a plurality of read path terminals for evaluation of the logic state. The electrically insulating layer promotes electrical isolation between the read path and the write path and magnetic coupling of the read path to the write path.

Nonvolatile magnetic logic device

A nonvolatile alternative to DRAM or Flash is disclosed. It involves a new 'magnetic shift register' that avoids the bit annihilation problem that plagues magnetic racetrack memories. Using this new 'chainlink memory' approach, one avoids the annihilation problem inherent in racetrack memory by breaking up the racetrack into magnetically coupled links, where each link preferably handles one bit exclusively. Depending upon the implementation, the &#x201c;bit&#x201d; can be, for example, the magnetization of a link, presence or absence of a domain wall, or the polarity of a domain wall. Numerous examples and applications of this new chainlink technology are disclosed.

Growing community of inventors

Pittsburgh, PA, United States of America

David M Bromberg