Transmission Mossbauer spectroscopy on pulsed-laser-deposited thick Fe andNi-Zn ferrite films

Mossbauer spectroscopy with Fe-57 is used to characterize pulsed-laser-depo sited (PLD) Ni0.6Zny-Fe2O4 films is demonstrated. Mossbauer spectra were re corded as a function of film thickness (3-16 mu m) for films deposited in b ackground O-2 pressures of 50 and 200 mTorr, and for a zinc concentration o f y = 0.72. A spectrum was also recorded for y = 0.4 deposited in a backgro und pressure of 200 mTorr. The site occupancy was determined for the tetrah edral (A) and octahedral (B) sites. Results obtained here show that the eff ect of increasing the Zn is to shift Fe(tet) to Fe(oct). When compared with previous Mossbauer measurements on the bulk NiZn ferrites, the ferrite fil ms give spectra of similar quality with no visible evidence of clustering o r multiple phases present. The same linewidth was found for a PLD processed Fe film and a Mossbauer standard 70-mu m-thick alpha-Fe enriched foil. The Fe film had a magnetic hyperfine field of 334 kOe and no evidence of the p resence of any iron oxides. Good spectra may be obtained by selecting subst rates with low mass and low atomic number. We were successful in obtaining measurable Mossbauer spectra for films deposited on 0.5-mm-thick MgO, sapph ire, and alumina substrates whereas films deposited on Si, GaAs, and cubic zirconia substrates did not give good spectra. (C) 1999 American Institute of Physics. [S0003-6951(99)04345-4].