Method of writing to scalable magnetoresistance random access memory element
AssigneeMotorola, Inc.
InventorsLeonid Savtchenko, Bradley N. Engel, Nicholas D. Rizzo, Mark F. Deherrera, Jason Allen Janesky
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Abstract
A method to switch a scalable magnetoresistive memory cell including the steps of providing a magnetoresistive memory device sandwiched between a word line and a digit line so that current waveforms can be applied to the word and digit lines at various times to cause a magnetic field flux to rotate the effective magnetic moment vector of the device by approximately 180°. The magnetoresistive memory device includes N ferromagnetic layers that are anti-ferromagnetically coupled. N can be adjusted to change the magnetic switching volume of the device.
Claims31
A method of switching a magnetoresistive memory device comprising the steps of:
- providing a magnetoresistive memory element adjacent to a first conductor and a second conductor wherein the magnetoresistive memory element includes a pinned magnetic region and a free magnetic region separated by a tunneling barrier, the free magnetic region includes N anti-ferromagnetically coupled layers of a ferromagnetic material, where N is an integer greater than or equal to two, and where the N layers define a volume and each layer of the N layers has a moment adjusted to provide a writing mode, and wherein a sub-layer magnetic moment fractional balance ratio of the one of the first and second magnetic regions is in a range 0≦|Mbr|≦0.1, and the free magnetic region has a magnetic moment vector adjacent to the tunneling barrier oriented in a preferred direction at a time t0;
- and
- applying a word current pulse to one of the first and second conductors at a time t1 and turning off the word current pulse at a time t3 while additionally applying a digit line current pulse to another of the first and second conductors at a time t2 and turning off the digit line current pulse at a time t4, wherein t0<t1<t2<t3<t4 so that the magnetic moment vector of the free magnetic region adjacent to the tunneling barrier at the time t4 is oriented in a direction different from the initial preferred direction at the time t0.
A method of switching a magnetoresistive device comprising the steps of:
- providing a magnetoresistive device adjacent to a first conductor and a second conductor wherein the magnetoresistive device includes a free magnetic region and a fixed magnetic region separated by a tunneling barrier, the free magnetic region including an N layer synthetic anti-ferromagnetic structure that defines a volume, where N is an integer greater than or equal to two, the N layer synthetic anti-ferromagnetic structure includes anti-ferromagnetically coupled ferromagnetic layers with an magnetic moment vector adjacent the tunneling barrier oriented in a preferred direction at a time t0, and the N layer synthetic anti-ferromagnetic structure is adjusted to provide a toggle write mode;
- reading an initial state of the magnetoresistive memory device and comparing the initial state with a new state to be stored in the magnetoresistive memory device;
- and
- applying a word current pulse, only if the initial state and the new state to be stored are different, to one of the first and second conductors at a time t1 and turning off the word current pulse at a time t3 while additionally applying a digit line current pulse to another of the first and second conductors at a time t2 and turning off the digit line current pulse at a time t4.
Dependencies are inferred from the claim text.