Transverse magnetization in Cu/Ni/Cu epitaxial nanorings

The micromagnetic structure in epitaxial (001)-oriented Cu/Ni(14 nm)/Cu rings fabricated by electron beam and focused ion beam lithographies with external diameter of 3 µm and linewidths between 100 and 500 nm is presented. We found that a state with radial orientation of the magnetization prevails at remanence. The evaluation of the magnetoelastic, magnetocrystalline and magnetostatic energies shows that a value as low as 1.5 × 10-3 for the anisotropic relaxation of the in-plane strain components is enough to induce an effective radial easy magnetization direction

Magnetoelastic stresses in rare-earth thin films and superlattices

We report on the study of the magnetoelastic behavior of some rare-earth based thin films and superlattices (SL`s). Magnetoelastic stress (MS) measurements (by using a cantilever capacitive technique) within a wide range of temperatures (10-300 K) and magnetic fields (up to 12 T) have been performed. We derive expressions relating the cantilever curvatures and the magnetoelastic stresses in anisotropic thin films and SL`s (for cubic symmetry) deposited onto crystalline substrates. The magnetoelastic energy associated to the interfaces and the epitaxial stress dependence of the volume MS has been investigated by studying the basal plane MS in Hon/Lu₁₅ and in Ho₁₀/Ym SL`s: we obtain interface MS even higher than the volume ones and the effect in bulk`s MS of the epitaxial strain is large. In Dy/Y and Er/Lu SL's we also deduce the MS contributions but, for Er/Lu, incomplete saturation leads to inconclusive results. Although the latter case also happens in Ho/Tm SL`s, MS clearly shows anisotropy competition. In TbFe₂ (t) / YFe₂(1000 Å) (300 Å < t < 1300 Å) epitaxial bilayers, we determine all the MS allowed by the symmetry and show that epitaxial stress strongly modifies the tetragonal MS. The thermal dependence of MS parameters is also analysed

Magnetoelasticity in dysprosium-scandium superlattices

We have studied the magnetoelastic stress parameter, Bγ,2, associated with the shear deformation within the basal plane of the (0 0 0 1) Dy (20 Å)/Sc (t=20–60 Å) superlattices (SLs). The extrapolated Bγ,2(0 K) values change from 1.45 to 0.9 GPa when t changes from 60 to 20 Å, respectively. All SLs show a thermal behavior of Bγ,2 affected by volume and interfacial contributions. The scandium thickness dependence of the volume contribution shows a surprisingly logarithmic behavior that indicates the existence of dislocations in the Dy blocks

High Pulsed Field Measurements of the Magnetic Anisotropy in (Er1-xDyx)2Fe14B Compounds

A study of HA in pseudoternaries (ErxDy1-x2Fe14B has been undertaken using the SPD technique on magnetically oriented samples. We have determined the temperature dependence of HA for several compounds in the range of concentration 0.5 ≤ x ≤ 1. Substitution of Er3+ ions by Dy3+ ions produces a significant modification in HA and also in the spin reorientation (SRT) processes

Determination of magnetostrictive stresses in magnetic rare-earth superlattices by a cantilever method

The magnetostrictive stress for a Ho6/Y6 superlattice has been determined at low temperatures by means of a capacitive cantilever technique. The magnetostrictive stress responsible for the basal plane distortion is found to be strongly enhanced with respect to bulk holmium. An explanation accounting for the unusual thermal dependence of that stress is offered

High Pulsed Field Measurements of the Magnetic Anisotropy in (ErxNd1-x)2Fe14B

Measurements of the anisotropy and critical fields of first order transitions (FOMP) have been performed as a function of both temperature and composition in the system (ErxNd1−x)2Fe14B. Competing anisotropies give rise to multiple and complex spin reorientation transitions and different types of FOMP