Magnetic properties of nanocrystalline γ-Fe–Ni–N nitride systems

Abstract

Articles you may be interested inSpin glasslike behavior and magnetic enhancement in nanosized Ni-Zn ferrite system J. Appl. Phys. 108, 034307 (2010); 10.1063/1.3456174Mössbauer spectroscopic and x-ray diffraction studies of structural and magnetic properties of heat-treated ( Ni 0.5 Zn 0.5 ) Fe 2 O 4 nanoparticles Nanocrystalline ␥-Fe 0.75 Ni 0.25 -N, ␥-Fe 0.5 Ni 0.5 -N, and ␥-Fe 0.25 Ni 0.75 -N nitrides have been synthesized by borohydride reduction followed by nitridation at 773 K using NH 3 (g). ␥-Fe 0.75 Ni 0.25 -N, ␥-Fe 0.5 Ni 0.5 -N and ␥-Fe 0.25 Ni 0.75 -N nitrides crystallize in fcc cubic structures having unit cell parameters: aϭ3.588, 3.556 and 3.534 Å, respectively. X-ray diffraction and electron microscopic studies reveal the ultrafine nature of the particles. Chemisorption of atmospheric oxygen results in the formation of nonmagnetic oxide and/or a complex oxynitride layer at the surface of the ultrafine particles. The reduction of room temperature saturation magnetization is attributed to fine particle size effects and the formation of nonmagnetic oxide and/or an oxynitride layer at the surface of the ultrafine particles. The change in Curie temperature T c in ␥-Fe-Ni-N nitride systems compared to their corresponding bulk Fe-Ni alloys is related to the presence of concentration inhomogeneities in the nitride materials. Mössbauer study of ␥-Fe 0.75 Ni 0.25 -N, ␥-Fe 0.5 Ni 0.5 -N and ␥-Fe 0.25 Ni 0.75 -N nitride particles exhibit the coexistence of ferromagnetic and superparamagnetic fractions and corroborate the observed magnetic properties.

Effect of Ni concentration on the structure and magnetic properties for nanocrystalline Fe–Ni–N thin films

“…The addition of the third element into Fe-N to form ternary Fe-M-N films (M = Ta, Zr, Hf, Nb, etc.) [17][18][19][20][21][22] succeeds in solving the soft magnetic and thermal stability problems. Kopcewicz et al [19] have studied the role of alloying elements such as Cr, Al, Ti and Mn, in the formation and stability of the nitride phases using conversion electron Mössbauer * Corresponding author.…”

“…spectroscopy and found that the presence of alloying elements, especially Ti, significantly extends the range of the thermal stability of ␣ -martensite at low N doses and ␥ -Fe 4 N at high N doses toward higher temperatures. Panda and Gajbhiye [20] have synthesized nanocrystalline ␥-Fe-Ni-N systems using the borohydride reduction route and the roles of interstitial nitrogen and fine particle size and surface effects have been studied with regard to the structure and magnetic properties. Some groups [23][24][25][26][27][28] have reported the dependence of the saturation magnetization, lattice parameter or coercive field on the Ni content for other nanocrystalline FeNiN compounds.…”

Magnetic properties of (Fe)1−x–(Al2O3)x and (Fe50Ni50)1−x–(Al2O3)x nanocomposite magnetic media synthesized using gel like Al2O3 matrix

“…The two types of nanocomposite magnetic media studied in the present work are Fe 1−x -(Al 2 O 3 ) x and (Fe 50 Ni 50 ) 1−x -(Al 2 O 3 ) x where 'x' is varied from 0 wt.% to 15 wt.%. These materials have been chosen because Fe is the classical soft ferromagnetic element while Fe 50 Ni 50 is a soft ferromagnetic alloy [12][13][14][15]. Both these have technological applications in areas such as magnetic information storage, high frequency magnetoresistance and medical diagnostics [16][17][18].…”

Low Temperature Isothermal Reduction Kinetics of Fe<SUB>2</SUB>O<SUB>3</SUB>/NiO Mixed Oxides and Comparative Synthesis of Fe<SUB>1&minus;<I>x</I></SUB>Ni<I><SUB>x</SUB></I> Alloys

“…[7][8][9][10][11] Slight variation of the composition in the Fe-Ni alloy can cause substantial changes in the coercive, anisotropic and magnetostrictive properties. 12) An important feature of the Fe-Ni alloy system is its structural evolution, with a change from bcc for the Fe-rich alloy to fcc for the alloy with larger Ni content. 13) Jartych et al 14) found that in the case of Fe-Ni alloys the bcc solid solution was formed during high-energy ball milling for the composition with 20 at% Ni, while around 35 at% Ni the fcc solid solutions were obtained.…”