Hongge Pan

Structure and magnetic properties of TbMn6−xAlxSn6 compounds

In the present work, the influence of the substitution of Al for Mn on the structure and magnetic properties of TbMn6−xAlxSn6 compounds was investigated. With increasing Al concentration the lattice constants a, c, and the unit-cell volume V decrease monotonically. The TbMn6−xAlxSn6 compounds exhibit ferrimagnetic ordering. The magnetic ordering temperature first decreases with increasing Al content up to x=1.5, then increases with further increasing Al content. As for the unsubstituted material, it was found that this series of compounds exhibits a second magnetic transition at lower temperature that is attributed to spin reorientation. The spin-reorientation temperature and the magnetic anisotropy field first decrease with increasing Al content, go through a minimum at x=0.5, then increase with further increasing Al content. The saturation magnetization decreases monotonically with increasing Al content. Two metamagnetic transitions are found in TbMn6Sn6 compounds, one at 0.44 T, and the other at about ...

Structure and magnetic properties of Y2Fe17−xMnx compounds (x = 0–6)

The effect of Mn on structure and magnetic properties of Y2Fe17−xMnx compounds has been studied. Substitution of Mn for Fe does not change the structure of Y2Fe17, and all the Y2Fe1−xMnx compounds crystallize in Th2Ni17 structure. The lattice constants first increase, then slightly decrease, and finally increase again. The Curie temperature of Y2Fe17−xMnx compounds first increases, shows a maximum atx = 0.3, the decreases again. The saturation magnetization of Y2Fe1−xMnx compounds decreases dramatically with increasing Mn content. The moments of Mn atoms in these compounds are also discussed.

Magnetic properties of a new series of rare-earth iron nitrides (R = Ce, Nd, Sm, Gd, Tb, Dy or Y)

A series of interstitial nitrides R(3)(Fe, Mo)(29)N-x with 3.7 less than or equal to x less than or equal to 4.0 has been prepared for R = Ce, Nd, Sm, Gd, Tb, Dy or Y. The nitrides have structures related to Nd-3(Fe,Ti)(29), but the unit-cell volumes are 4.7-6.6% greater and the magnetic ordering temperatures some 224-361 K higher than those of the R(3) (Fe, Mo)(29) parent compounds, and the saturation magnetizations Ms are also higher than those of the corresponding parent compounds. All compounds investigated exhibit easy-plane anisotropy at room temperature, except for Sm-3(Fe, Mo)(29)N-x which is of an easy-axis nature.

Formation, structure and magnetic properties of Y3(Fe,Mo)29 intermetallic compound

A novel single-phase Y-3(Fe,Mo)(29) compound with Mo as a new stabilizing element has been synthesized with nominal composition Y10.5Fe86.7Mo2.8 via annealing at 1313 K for three days, and then water quenching. The results of thermomagnetic analysis (TMA) show a magnetic ordering temperature of 376 K. X-ray diffraction gives lattice parameters a = 10.570 Angstrom, b = 8.508 Angstrom, c = 9.673 Angstrom and beta = 96.98 degrees. The temperature dependence of the magnetization M(s) of Y10.5Fe86.7Mo2.8 in an applied magnetic field up to 7 T and the temperature dependence of the anisotropy field B-a are also reported.

Volume expansion and Curie temperature enhancement in R3(Fe, M)29 (M=Mo and V) and their nitrides

In the present paper, based on the investigation of the structure and magnetic properties of R-3(Fe, M)(29) (M=Mo and V) and their nitrides, a study on the effect of the volume change due to the nitrogenation on the Curie temperature of these compounds has been performed. The (d In T-C)/(d In V) values were derived by comparing the change of the Curie temperature and volume before and after nitrogenation. Our results indicate that the relationship between (d In T-C)/(d In V) and Curie temperature T-C agrees with an itinerant electron model formalism

A study on the exchange interaction in R2Fe17 compounds

A study on the exchange interaction in R2Fe17 compounds (R represents the heavy rare earth elements) has been performed by means of a mean‐field analysis of the high‐field magnetization curves, which were measured on the powder samples. Measurements have been carried out on R2Fe17‐based quasiternary R2Fe17−xMx compounds with R=Dy, Ho, and Er, M=Al, Ga, and Si. It has been found that the value of the exchange coupling constant decreases with increasing atomic number of R ion of the compound. This behavior is explained by the varying 4f–5d hybridization in the compounds.

Investigation of the coercivity of FeSiO2 fine particles assembly prepared by high energy ball milling

Abstract FeSiO 2 fine particle assembly, prepared by high-energy ball milling, exhibits coercivity which is enhanced by two orders of magnitude with respect to the α-iron. With increasing the fraction of x v from 0.3 to 0.6, the coercivity of Fe x (SiO 2 ) 1−x decreases from 350 Oe to 50 Oe. The coercivity of milled Fe 0.3 (SiO 2 ) 0.7 first increases, undergoes a peak and then decreases, with increase in the deviation angle between the direction of external field and the aligned direction of the magnetically aligned powder-bonded samples. The magnetic reversal of FeSiO 2 fine particles assembly can be explained by incoherent rotation for small values of deviation angles, and by coherent rotation for large values of small deviation angles.