FMR study of the crystalline anisotropy of [Fe(t)Cr(38Å)]N superlattices grown on MgO(100) and MgO(110)

Using ferromagnetic resonance we measured the magnetocrystalline anisotropy (MA) of [Fe(t)Cr(38)]N superlattices with t: 5, 10, 14, 25, and 100 Angstrom, grown on MgO(100) and MgO(110) (SL100 and SL110, respectively). In the SL100 (SL110) series the effective demagnetization decreases due to a large surface MA of 0.19 +/-0.04erg/cm(2) (0.40 +/-0.05 erg/cm(2)). In SL100 the cubic MA, K-C, approaches the bulk value for large t and decreases as 1/t. In SL110 we found a similar behavior of K-C(t) which was not noted before as well as an uniaxial MA that increases as 1/t. The MA collapse for t=5 Angstrom, which we attribute to interface disorder. (C) 2001 Published by Elsevier Science B.V.