B Nasunjilegal

Magnetic properties of a novel Sm3(Fe, Ti)29 phase

Abstract In a systematic study of the Sm 10 Fe 85 Ti x (4.7 x 3 (Fe, Ti) 29 compound has been found to be a new phase, of which the structure is Nd 3 (Fe, Ti) 29 -type. The X-ray diffraction pattern of Sm 3 (Fe 0.933Ti 0.06 7) 29 can be indexed on the monoclinic symmetry with the lattice parameters a = 1.065 nm, b = 0.858 nm, c = 0.972 nm and β = 96.98°. The Sm 3 (Fe 0.933 Ti 0.067 ) 29 compound exhibits ferromagnetic ordering with a Curie temperature T C = 486 K. The saturation magnetization M S is 125 A m 2 /kg at 77 K and 119 A m 2 /kg at room temperature. The room temperature anisotropy field is 3.4 T.

MAGNETIC-PROPERTIES OF A NOVEL SM3(FE, TI)29NY NITRIDE

A new interstitial nitride of Sm3(Fe0.933Ti0.067)29Ny (y=5) has been synthesized. Its x‐ray pattern can be indexed in Nd3(Fe,Ti)29‐type monoclinic symmetry with the lattice parameters of a=1.098 nm, b=0.882 nm, c=0.985 nm, and β=97.50°. The Sm3(Fe0.933Ti0.067)29Ny nitride exhibits ferromagnetic ordering with a Curie temperature Tc=750 K. The saturation magnetization Ms is 160 A m2/kg at 4.2 K and 140 A m2/kg at 293 K. The anisotropy field is 18.1 T at 4.2 K and 12.8 T at 293 K. The coercivity of μ0iHc=0.83 T at 293 K on this new nitride has been developed.

Magnetic properties of R3(Fe,Ti)29Cy carbides (R=Nd, Sm)

R3(Fe, Ti)29Cy carbides (R=Nd, Sm) have been synthesized by gas-solid phase reaction. The Curie temperature is enhanced by carbonation, with values of 651 K and 641 K for Nd and Sm carbides respectively. The saturation magnetization of the carbides is slightly lower than that of their parent alloys. The Sm carbide has a large uniaxial anisotropy field, 21 T at 4.2 K and 14 T at 293 K. A coercivity of mu 0iHc=0.3 T at room temperature in the Sm carbide has been developed.

Formation and magnetic properties of Sm3(Fe,Ti)29Ny compounds

The formation and magnetic properties of a novel intermetallic Sm3(Fe0.933Ti0.067)29 compound and the Sm3(Fe0.933Ti0.067)29Ny (y=5) nitride have been investigated. The x-ray diffraction patterns of the nitride and the parent compound were indexed on the basis of the Nd3(Fe,Ti)29-type structure with monoclinic symmetry. The parent and the nitride exhibit ferromagnetic ordering with a Curie temperature TC of 486 K for the parent and 750 K for the nitride. Introduction of nitrogen led to an increase in saturation magnetization; Ms for the nitride is 160 A m2 kg-1 at 4.2 K and 140 A m2 kg-1 at 293 K. The nitride has a uniaxial anisotropy with an anisotropy field strength Ba for 25 T at 4.2 K and 12.8 T at 293 K. The coercivity mu 0iHc=0.83 T at 293 K for this new nitride has been determined.

A hard magnetic property study of a novel Sm3(Fe,Ti)29Ny nitride

The hard magnetic properties of a new interstitial nitride Sm3(Fe0.933Ti0.067)29Ny (y approximately 5) have been investigated by ball milling. The saturation magnetization linearly decreases with ball-milling time. By ball milling, maxima of remanence Br=1.04 T, intrinsic coercivity mu 0iHc=0.83 T and energy product (BH)max=105 W m-3 are achieved at 293 K.

Novel permanent magnetic material: Sm3(Fe,Ti)29Ny

Abstract The X-ray diffraction pattern of the novel Sm 3 (Fe 0.933 Ti 0.067 ) 29 compound was indexed on the basis of monoclinic symmetry with the lattice parameters a = 1.065 nm, b = 0.858 nm, c = 0.972 nm and β = 96.98°. The Sm 3 (Fe 0.933 Ti 0.067 ) 29 compound exhibits ferromagnetic ordering with T C = 486 K and a planar anisotropy. The new interstitial nitride of the Sm 3 (Fe 0.933 Ti 0.067 ) 29 N 5 compound was obtained by gas-solid phase reaction. The nitride has the same structure as the parent compound. The introduction of nitrogen leads to an increase in the Curie temperature to 750 K. The saturation magnetization values σ s = 160 A m 2 kg −1 at 4.2 K and 140 A m 2 kg −1 at 293 K. The anisotropy was changed from planar to uniaxial upon nitrogenation. The anisotropy field B a values were 18.1 T at 4.2 K and 12.8 T at 293 K. The hard magnetic properties of the Sm 3 (Fe 0.933 Ti 0.066 ) 29 N 5 compound have been studied. A coercivity μ 0i H c value of 0.83 T and a maximum energy product ( BH ) max of 105 kJ m −3 at 293 K have been achieved. The Sm 3 (Fe 0.933 Ti 0.067 ) 29 Ny compound is a promising material for permanent magnetic applications.

Crystal fields in R3(Fe, Ti)29Ny

Abstract Point-charge calculations yield crystal field coefficients A 20 (R) in R 3 (Fe, Ti) 29 of −285 K a 0 −2 for the 4e site and +191 K a 0 −2 for the 2a site. Bonding charge model calculations show that the N-induced shift in A 20 is ΔA 20 = −187 K a 0 −2 for R 3 (Fe, Ti) 29 N 4 .

Hard magnetic behaviour and interparticle interaction in the Sm3(Fe, Ti)29Ny nitride

The coercivity of the Sm3(Fe,Ti)29Ny nitride is controlled by the nucleation mechanism. The phenomenon of a minimum of the coercivity in the angular dependence of the coercivity is found for the Sm3(Fe,Ti)29Ny nitride. The small magnetizing field required to obtain the saturation coercivity and the small interparticle interaction for the isotropic Sm3(Fe, Ti)29Ny magnet imply that grains of Sm3(Fe, Ti)29Ny are well isolated.