Magnetic memory device and method of writing magnetic memory device

Abstract

Embodiments provide a magnetic memory device and a method of writing a magnetic memory device. The magnetic memory device includes a magnetic tunnel junction including a reference layer, a free layer and a tunnel barrier layer between the reference and free layers, and a first conductive line adjacent to the free layer. A first spin-orbit current having a frequency decreasing with time flows through the first conductive line. The writing method includes applying the first spin-orbit current having the frequency decreasing with time to the first conductive line.

1 . A method of writing a magnetic memory device including a magnetic tunnel junction having a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer, and a first conductive line adjacent to the free layer, the method comprising:
 applying a first spin-orbit current having a frequency decreasing with time to the first conductive line.   
     
     
         2 . The method as claimed in  claim 1 , wherein:
 the magnetic tunnel junction is on a first surface of the first conductive line, and   the free layer is between the tunnel barrier layer and the first surface of the first conductive line.   
     
     
         3 . The method as claimed in  claim 1 , wherein applying the first spin-orbit current applies a spin-orbit torque to a magnetic moment of the free layer. 
     
     
         4 . The method as claimed in  claim 1 , wherein:
 the first spin-orbit current has an initial frequency when applying the first spin-orbit current starts,   a magnetic moment of the free layer has an initial natural frequency when applying the first spin-orbit current starts, and   the initial frequency of the first spin-orbit current is equal to or greater than the initial natural frequency of the magnetic moment of the free layer.   
     
     
         5 . (canceled) 
     
     
         6 . The method as claimed in  claim 1 , wherein applying the first spin-orbit current generates at least two resonances at which a frequency of the first spin-orbit current coincides with a natural frequency of a magnetic moment of the free layer. 
     
     
         7 . The method as claimed in  claim 6 , wherein the frequency of the first spin-orbit current is greater than the natural frequency of the magnetic moment of the free layer between the at least two resonances. 
     
     
         8 . The method as claimed in  claim 1 , further comprising:
 applying a spin-transfer current passing through the magnetic tunnel junction.   
     
     
         9 . The method as claimed in  claim 8 , wherein the spin-transfer current is applied after the applying of the first spin-orbit current. 
     
     
         10 . The method as claimed in  claim 8 , wherein the spin-transfer current and the first spin-orbit current are applied at the same time for at least a certain period of time. 
     
     
         11 .- 12 . (canceled) 
     
     
         13 . The method as claimed in  claim 1 , wherein the magnetic memory device further comprises: a second conductive line intersecting the first conductive line, the method further comprising:
 applying a second spin-orbit current having a frequency decreasing with time to the second conductive line.   
     
     
         14 . The method as claimed in  claim 13 , wherein the magnetic tunnel junction is disposed on a crossing point of the first and second conductive lines. 
     
     
         15 . The method as claimed in  claim 13 , wherein the frequency of the first spin-orbit current is equal to the frequency of the second spin-orbit current. 
     
     
         16 . (canceled) 
     
     
         17 . A method as claimed in writing a magnetic memory device including a magnetic tunnel junction having a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer, and a first conductive line adjacent to the free layer, the method comprising:
 applying a first spin-orbit current to a first conductive line in the magnetic memory device, wherein applying the first spin-orbit current generates at least two resonances at which a frequency of the first spin-orbit current coincides with a natural frequency of a magnetic moment of the free layer.   
     
     
         18 . The method as claimed in  claim 17 , wherein the frequency of the first spin-orbit current is greater than the natural frequency of the magnetic moment of the free layer between the at least two resonances. 
     
     
         19 .- 20 . (canceled) 
     
     
         21 . The method as claimed in  claim 17 , wherein:
 the first spin-orbit current has an initial frequency when applying the first spin-orbit current starts,   the magnetic moment of the free layer has an initial natural frequency when the applying of the first spin-orbit current starts, and   the initial frequency of the first spin-orbit current is equal to or greater than the initial natural frequency of the magnetic moment of the free layer.   
     
     
         22 . (canceled) 
     
     
         23 . The method as claimed in  claim 17 , wherein the magnetic memory device further includes a second conductive line intersecting the first conductive line, the method further comprising:
 applying a second spin-orbit current to the second conductive line.   
     
     
         24 .- 34 . (canceled) 
     
     
         35 . A method of writing a magnetic memory device including a magnetic tunnel junction having a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer, and a first conductive line adjacent to the free layer, the method comprising:
 applying a first spin-orbit current including
 initially applying the first spin-orbit current having an initial frequency at a first time to the first conductive line; and 
 subsequently applying the first spin-orbit current having a subsequent frequency, less than the initial frequency, at a second time to the first conductive line, the second time after the first time. 
   
     
     
         36 . The method as claimed in  claim 35 , wherein:
 a magnetic moment of the free layer has an initial natural frequency when applying the first spin-orbit current starts, and   the initial frequency of the first spin-orbit current is equal to or greater than the initial natural frequency of the magnetic moment of the free layer.   
     
     
         37 . The method as claimed in  claim 35 , further comprising:
 applying a spin-transfer current passing through the magnetic tunnel junction.   
     
     
         38 . The method as claimed in  claim 35 , wherein applying the first spin-orbit current generates at least two resonances at which a frequency of the first spin-orbit current coincides with a natural frequency of a magnetic moment of the free layer.