Magnetoresistive device, method for changing resistance state thereof, and synapse learning module
The present disclosure relates to a field of memory technical, and in particular to a magnetoresistive device, a method for changing a resistance state of the magnetoresistive device, and a synapse learning module. The magnetoresistive device includes a top electrode, a ferromagnetic reference layer, a tunneling layer, a ferromagnetic free layer, a spin-orbit coupling layer, and a bottom electrode that are arranged in sequence along a preset direction, where the spin-orbit coupling layer includes a first thickness region and a second thickness region distributed alternately, and a thickness of the first thickness region is different form a thickness of the second thickness region; and the ferromagnetic free layer includes a pinning region, and a position of the pinning region is in one-to-one correspondence with a position of the first thickness region.
1 . A magnetoresistive device, comprising a top electrode, a ferromagnetic reference layer, a tunneling layer, a ferromagnetic free layer, a spin-orbit coupling layer, and a bottom electrode that are arranged in sequence along a preset direction, wherein:
the spin-orbit coupling layer comprises a first thickness region and a second thickness region distributed alternately, and a thickness of the first thickness region is different from a thickness of the second thickness region;
the ferromagnetic free layer comprises a pinning region, and a position of the pinning region is in one-to-one correspondence with a position of the first thickness region; and
the magnetoresistive device further comprises a Dzyaloshinski-Moriya interaction (DMI) enhancement layer, wherein the DMI enhancement layer is located between the tunneling layer and the ferromagnetic free layer.
2 . The magnetoresistive device according to claim 1 , wherein the thickness of the first thickness region is greater than the thickness of the second thickness region.
3 . The magnetoresistive device according to claim 1 , wherein a material of the DMI enhancement layer comprises at least one of Ti, Cu, W, Ta, or Al.
4 . The magnetoresistive device of claim 1 , wherein the ferromagnetic free layer comprises N pinning regions, and the magnetoresistive device comprises (N+2) resistance states.
5 . The magnetoresistive device of claim 1 , wherein:
a material of the ferromagnetic reference layer comprises at least one of CoFeB, CoFe, or a composite material of Co/Pt;
a material of the ferromagnetic free layer comprises at least one of CoFeB, CoFe, or a composite material of Co/Pt; and
a material of the tunneling layer comprises at least one of MgO or Al 2 O 3 .
6 . The magnetoresistive device according to claim 1 , wherein a material of the spin-orbit coupling layer comprises at least one of W, Ta, or Pt.
7 . A method for changing a resistance state of the magnetoresistive device according to claim 1 , comprising:
applying a modulation driving current to the magnetoresistive device, wherein the modulation driving current acts on the spin-orbit coupling layer; and
changing a characteristic of the modulation driving current, so as to change the resistance state of the magnetoresistive device.
8 . The method according to claim 7 , wherein the changing a characteristic of the modulation driving current comprises:
changing at least one of a pulse width, a pulse amplitude, a pulse number, or a pulse direction of the modulation driving current.
9 . A synapse learning module comprising the magnetoresistive device according to claim 1 , comprising:
a training unit configured to generate a writing pulse according to an arrival order of a pre-neuron signal and a post-neuron signal, and a time interval between the pre-neuron signal and the post-neuron signal; and
a synapse device comprising the magnetoresistive device, wherein the top electrode and the bottom electrode of the magnetoresistive device are connected to the training unit.