Effects of Ti addition on the soft magnetic properties of Fe - N films

Abstract

FeTiN films with good soft magnetic properties were prepared on Si and NaCl single-crystal substrates by facing-targets sputtering (FTS). The effects of Ti addition on the structural and magnetic properties of Fe - N films were investigated. Ti has been found effective in improving the soft magnetic properties as well as the thermal stability of FeN films. For the films containing 5 - 12 at.% Ti prepared under sputtering conditions of = 0.04 - 0.07 Pa, a substrate temperature of , and a sputtering rate of , the following properties are observed: very high saturation magnetization (2.3 - 2.5 T), low coercivity (160 - 240 ), and high relative permeability (3000 - 3500 at 1 MHz). The thermal stability of these films was also found to be good, e.g. was less than and was higher than 2.3 T for the films annealed up to . The crystal structures of the FeTiN films were examined with an x-ray diffractometer and a transmission electron microscope. Ti addition affects the formation of magnetic iron nitride phases and makes the crystallites small. The fine-grained Fe - N phase, together with finely dispersed TiN precipitates, is considered to be one of the main factors responsible for the good magnetic properties and thermal stability.

Magnetic properties and structural implications for nanocrystallineFe−Ti−Nthin films

“…Part A presents room temperature FMR results that show a clear signature of a deposition field induced uniaxial anisotropy. The uniaxial field parameter increases with N x for nitrogen levels above about 4 at. %.…”

“…It has been found that the addition of small amounts of a third element Q to form ternary Fe-Q-N phases, typically Hf, Ta, Ti, or Zr, can serve to increase thermal stability. 4,16,17 For pure iron, additions of such a Q element at levels up to about 5 at. % have been found to dissolve substitutionally into the bcc lattice with no substantial effect on the structure or magnetic properties.…”

“…II, there is a structural transition somewhere in the 0. 4 11 N x < < at. % range for Fe-N, and it is reasonable to expect a similar effect for Fe-Ti-N. X-ray data by Ding et al, 6 on films similar to those studied here do indicate a structural change.…”

Effect of dopants on thermal stability and self-diffusion in iron-nitride thin films

“…In attempts to make interstitial Fe-N more stable, addition or doping of impurity element(s) was proposed in such a way * mgupta@csr.res.in/dr.mukul.gupta@gmail.com that the amount of impurity must be low enough to affect the structural or the magnetic properties adversely [9,[21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Such impurity doped systems were termed as Fe-X-N with X = few at.…”

Microstructure of nanocrystalline FeZr(N)-films and their soft magnetic properties

“…It has been found that certain nitrogen-containing nanocrystalline films composed of iron with 1-10 at% of a transition element, like Ta, Ti, Cr, Zr [1][2][3][4] have good soft magnetic properties. For thin films (o200 nm), where eddy current losses are small, magnetic losses at high frequencies are mainly determined by the presence of ferromagnetic resonance (FMR) with a frequency f FMR Egð4pM s H K Þ 1=2 : Here, g is the gyromagnetic ratio (0.446 MHz/Oe), M s the saturation magnetization and H K the effective anisotropy field in the plane.…”