Magnetic anisotropy of sputtered Ni/Ag multilayers

We have studied the magnetic properties and structure of Ni/Ag multilayers, fabricated by the dc magnetron sputtering method. The in-plane uniaxial anisotropy, which is closely related to the sample preparation, has been detected by both vibrating magnetometer (VSM) and ferromagnetic resonance (FMR) measurements where the FMR spectra were obtained as a function of the applied magnetic field orientation in the film plane. The variation of the resonance field with the angle of the applied magnetic field can be well explained by a theoretical model including the in-plane uniaxial anisotropy up to the second-order term. Moreover, both in-plane and perpendicular anisotropy parameters have been deduced by a data-fitting analysis and a negative interface anisotropy constant has been determined.