Theoretical study of magnetostriction in FeTaN thin films

Abstract

Single layer films of FeTaN have been deposited by dc magnetron sputtering, and the relationships between the magnetostriction and film composition have been studied. A linear increase in magnetostriction with nitrogen content has been explained by the dependence of λ100 on nitrogen concentration. The form of this dependence has been derived based on a theory developed by De Vries for describing the magnetic after effect in iron films with interstitial nitrogen. At room temperature, the best fit for the experimental magnetostriction data was found for an interstitial interaction constant of D=4.18×106 J/m3. The total magnetic anisotropy energy per grain, U110, has also been calculated as a function of the strain for FeN films with a (110) orientation under a tetragonal deformation. This calculation used the results derived for the dependence of the magnetostriction constant, λ100, on nitrogen concentration. The calculated U110 value shows a minimum at a lattice strain value of ε11=0.0029, in close agreement with a maximum in permeability at Δd110/d110=0.0028 previously reported for FeN films.

Microstructure and magnetism in FeTaN films deposited in the nanocrystalline state

“…Extrapolated values for both Fe and FeTa nitrogen-free films are found comfortingly consistent with the values expected for ideal random and ͑110͒ plane-oriented bulk iron, according to the relations ͑9͒ and ͑10͒ from Ref. 31 As seen on Fig. 13, the magnetostriction in all the nitrogenated films is found to be very sensitive to the nitrogen incorporation.…”

“…Such a dependence has been previously reported in similar films 8 and explained on the basis of a theoretical description for nitrogenated-Fe system. 31 According to this model, the single-crystal constant 100 of Fe is expected to increase with N content according to the relation ͑11͒ 100 FeN ϭ 100…”

Reduced polynomial invariant integrity basis for in-plane magneto-mechanical loading

“…This is frequently observed for very thin magnetic materials used in high frequency electronic systems (the small thickness allows for a better homogeneity of the electromagnetic fields through the thickness at very high frequency, typically GHz). The textures encountered may vary but generally follow epitaxy rules (depending on the sublayer orientation): the direction normal to the layer is frequently a direction of strong crystalline symmetry [9,60,30].…”