MAGNETOSTRICTION CONSTANTS OF (110) ORIENTED EPITAXIALLY GROWN FETAN THIN-FILMS

The magnetostriction constants, lambda(100) and lambda(111), of FeTaN (10 wt% Ta) were determined in (110) oriented epitaxial thin films (si milar to 1500 Angstrom) deposited by de magnetron sputtering onto Cu(0 01) buffer layers (similar to 2000 Angstrom;) which were grown on Si(0 01) single crystal substrates, The orientation relationship of the fil ms was FeTaN(110)parallel to Cu(001)parallel to Si(001) wi th FeTaN < 111 >parallel to Cu < 110 > parallel to Si < 100 >, which was satisfie d by four different, equally probable in-plane orientations of the cry stallites. The magnetostriction measurement was carried out on a canti lever beam measurement system calibrated with (110) oriented epitaxial Fe films with the same morphology as the unknown films assuming the b ulk values of lambda(100) and h(111). The magnetostriction of FeTaN fi lms was measured as a function of angle in the sample plane and fitted with the calculated average of the four orientations, In conflict wit h theoretical predictions, it was found that lambda(100) decreases and lambda(111) increases as a function of lattice dilation which was tak en to be proportional to the interstitial concentration. At larger nor malized lattice dilation, similar to 2%, lambda(111) changed sign from negative to positive. The calculated saturation magnetostriction, lam bda(S), using these values of lambda(100) and lambda(111), agreed with published data on nanocrystalline samples of the same composition wit h no additional assumptions.