FeN phase generation effects for high moment FeTaN films

Abstract

FeN phase generation has been observed by x-ray analysis in FeTaN films, which normally show α-Fe, TaN phase, and no FeN phases. With a rise in substrate temperature Ts above 200 °C, FeN phases are generated in nitrogen reactive sputtering process with columnar structure formation, and remain after annealing. With FeN phase generation, coercivity Hc and magnetostriction λ values increase markedly. Moreover, internal stress σ for the films increases drastically. The FeTaN films, sputtered on low temperature substrate, generate no FeN phases, and show low Hc, about 0.1 Oe, and low λ. Consequently, FeN phase generation with columnar structure formation has negative effects for FeTaN films to be used as magnetic head core materials. For preparation of FeTaN films, the substrate temperature has to be controlled to a sufficiently low value for suppression of FeN phase generation.

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

“…results in superior thermal stability of Fe-N thin films. 15,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] These dopants either gets dissolved substitutionally into the Fe lattice or form a solid solution with Fe, which also creates some lattice distortion. Importantly, the qualifying thermodynamical variables that are required to enhance the thermal stability are high affinity (f ) and low heat of formation (∆H) of X-N as compared to Fe-N.…”

“…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.…”

Formation of iron nitride thin films with Al and Ti additives

“…Since early 1990s to recent years, various Fe-N thin films were studied by adding a tiny amount of a third element say X, it was observed that using such additives the limitations of binary Fe-N can be reduced to a great extent. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] The basic idea behind adding such element X was to chose an element which has more affinity to nitrogen than iron. When a third element X = Al, Ti, Ta, Zr etc.…”

“…Although many third elements have been used in Fe-X-N system, the choice of element X has been rather arbitrary. For example earlier works were mainly focused on Fe-Ta-N systems 10,12,13,15,17 , more recently other elements e.g. Ti 16,21,25,28 , Al 22,24 , Zr 20,23 and Rh 18 etc.…”

Structural and electrical properties of tantalum nitride thin films fabricated by using reactive radio-frequency magnetron sputtering

“…In order to obtain satisfactory overwrite performance of the recording process, the write head materials should inhabit superior properties such as very high saturation flux density B s of around 20 kG, high frequency permeability µ' of order 10 3 at 10 2-3 MHz, very low coercivity H c (say, <1 Oe), thermal stability up to 400-500 ºC and very small magnetostriction. One sort of the potential candidates for the new generation write head materials are the iron base thin films such as FeN, FeTaN and FeAlN [7][8][9][10][11][12]. To reduce the thermal noise induced by eddy current and to obtain excellent high frequency performance up to 10 2-3 MHz, various [Fe(Ta, Al)N/M] n multilayers have been synthesized and investigated, where M is representing for the interlayer, e.g., TaN, Ta, SiO 2 , Al 2 O 3 NiFe, CoZrRe, SiN, and AlN [12][13][14][15][16][17][18][19][20][21][22].…”