Acoustic excitation and detection of spin waves

Abstract

Apparatus for generating spin waves comprising a body (102) of magnetic material and an elastic wave generator (120), wherein the body (102) has a surface (108) and the elastic wave generator (120) is arranged to transmit elastic waves so that they propagate through the body (102) towards the surface (108) and are reflected at the surface to form a standing elastic wave in the body (102), thereby generating spin waves.

1 - 29 . (canceled) 
     
     
         30 . Apparatus for generating elastic waves from spin waves, the apparatus comprising a waveguide along which spin waves can propagate, a piezoelectric element, two electrodes located on opposite sides of the piezoelectric element, and an electrical connection between the two electrodes, wherein the piezoelectric element and the electrodes are mounted on the waveguide whereby propagation of spin waves along the waveguide will generate an oscillating electrical voltage across the piezoelectric element to generate an elastic wave. 
     
     
         31 . Apparatus according to  claim 30  further comprising an elastic wave detector arranged to detect the elastic wave thereby to generate a detection signal wherein the waveguide has first and second opposite sides, the piezoelectric element is located on a first one of the opposite sides, and the elastic wave detector is located on a second one of the opposite sides whereby the elastic waves will propagate through the waveguide between the piezoelectric element and the elastic wave detector. 
     
     
         32 . Apparatus according to  claim 31  wherein the piezoelectric element and the elastic wave detector are located on opposite sides of the waveguide so that the elastic wave will propagate through the waveguide between the piezoelectric element and the elastic wave detector. 
     
     
         33 . A method of detecting spin waves in a waveguide, the method comprising providing a piezoelectric element having first and second opposite sides, and a pair of electrodes each located on a respective one of the opposite sides, the electrodes having an electrical potential therebetween, and detecting variations in the electric potential thereby to detect the spin waves. 
     
     
         34 . Apparatus for generating elastic waves from spin waves, the apparatus comprising a waveguide in which spin waves can propagate, the waveguide having a surface, and a magnetostrictive element formed on the surface of the waveguide, whereby elastic deformation resulting from a spin wave propagating along the waveguide in the vicinity of the magnetostrictive element will generate an elastic wave propagating through the waveguide. 
     
     
         35 . Apparatus according to  claim 34  further comprising an elastic wave detector arranged to detect the elastic wave. 
     
     
         36 . Apparatus according to  claim 35  wherein the elastic wave detector comprises a piezoelectric device comprising a piezoelectric element and two electrodes arranged to detect a varying electric field in the piezoelectric element. 
     
     
         37 . Apparatus according to  claim 35  wherein the elastic wave detector is arranged opposite the magnetostrictive element on an opposing surface of the waveguide. 
     
     
         38 . Apparatus according to  claim 36  wherein the elastic wave detector is arranged opposite the magnetostrictive element on an opposing surface of the waveguide.