[en] Without annealing, Pr₁₃Fe_80-xCo_xC₅B₂ (x=0-20) ribbons with a coercive force of more than 1.0 T have been prepared by melt spinning. Due to Co addition, rectangularity of demagnetization curves is significantly improved. The remanence and maximum energy product of the samples are obviously increased with the increase of x (x≤15). A maximum energy product of 145.7 kJ/m³, which is the highest value among all that previously reported in the R₂Fe₁₄C-type (R=Nd or Pr) ribbons, has been achieved in the ribbons (x=15) prepared directly by melt spinning. The Curie temperatures of 2:14:1 carbides of the ribbons in the as-quenched state increase linearly with x at an average rate 12 K/at%Co. Similar to B and Cu, Co addition is found to accelerate the formation of 2:14:1 carbides

[en] Development of a superconducting magnet system for the 8 mm gyrotrone tube is discribed in this paper. Magnetic field at the axis of its main field coil has reached 2.14 T. Length of uniform region is 14.5 cm Degree of uniformity is ±3.84per mille. It could be operated in persistent mode by means of superconducting switch. Length of uniform region of the secondary field coil is 4.5 cm. Degree of uniformity is ±1.43per mille. Dewar vessel has a home temperature bore in step mode. The upper section diameter is 74 mm and the lower section is 140 mm. The average liquid helium boil-off rate of dewar vessel with superconducting magnet is 4 L/h

[en] The temperature dependent ⁵⁷Fe Moessbauer and X-ray diffraction measurement on Bi-system 2:2:2:3 phase have been carried out from 77 K to 300 K. It was found that there are two anomalous behaviors of lattice vibrational modes near 125 K and 220 K. This phenomena of lattice softening above T_c is taken as a precursor effect of superconductivity

[en] High-performance powders of NdFe_10.5V_1.5N_x with B_r=10.8 kG, H_cJ=4.3 kOe, (BH)_max=17.2 MGOe, and T_c>800 K were successfully prepared by using conventional milling process. The relationship of the crystallographic structure and the intrinsic magnetic properties to the nitrogen content is investigated. It is found that the nitrogen content is vital to obtain high-performance magnetic powders based on NdFe_10.5V_1.5N_x. In comparison with quenching Nd-Fe-B powders, NdFe_10.5V_1.5N_x powders are characterized by a larger maximum-energy product and a lower cost. Obviously, it is of significance in permanent magnet applications. (orig.)

[en] The crystal and magnetic structures, especially the site occupation of C atoms in the crystal cell of arc-melted PrFe_10.5Mo_1.1C_0.4 permanent magnetic alloy have been determined by means of powder neutron diffraction study. Rietveld analysis of the neutron diffraction data indicates that Mo atoms prefers the 8i site, about 76 percent of the C atoms occupy the 8i substitution site, and the other part of C atoms enter the 2b interstitial site. The exact molecular formula should be Pr(Fe_10.575Mo_1.250C_0.1.75C_0.055. It seems that the site occupation of C atoms in the ThMn₁₂-type carbides depends not only on the kind of substitutional transition metals, but also on the components of the substitutional transition metals in the compounds. There are still amount of work to make systematic studies on the relation between them. The effect of C atoms on the magnetic properties is also discussed. (author)

[en] The structural and magnetic properties of hydrides with ThMn₁₂-type structure have been studied by means of magnetic measurements, the neutron powder diffraction technique and self-consistent spin-polarized band calculations (LMTO-ASA). We found that the hydrides retain the ThMn₁₂-type structure, but with an increase of unit-cell volume. The neutron diffraction results indicate that hydrogen atoms occupy the interstitial 2b sites. Magnetic measurements carried out on YFe₁₀Mo₂, YFe_10.5V_x, YFe₁₁Ti and their hydrides show that both the Curie temperature and the saturation magnetization can be enhanced by introducing interstitial hydrogen atoms. Band-structure calculations and spin-fluctuation theory give a fair description of the enhancement of the magnetization and Curie temperature. (author)

[en] The structural and magnetic properties of a solution of carbon in YFe_10.5Mo_1.5 prepared by arc melting have been studied by means of magnetic measurements and the neutron powder diffraction technique. It was found that the carbides retain the ThMn₁₂-type structure but with an increase of unit-cell volume. The neutron diffraction results indicate that most of the carbon atoms occupy the interstitial 2b sites and the others occupy the substitutional 8i sites. According to the magnetic measurements, both the Curie temperature and the saturation magnetization are found to increase with the carbon concentration x in the YFe_10.5Mo_1.5C_x series, and the magnetocrystalline anisotropy is also affected by the carbon atoms. (author)

[en] Neutron powder diffraction studies indicate that PrFe_10.5Mo_1.5N_x retains the ThMn₁₂-type structure, and nitrogen atoms occupy the interstitial 2b sites. According to the structure parameters, the crystal-field coefficients of Pr³⁺ in the PrFe_10.5Mo_1.5 compounds and their nitrides were calculated using the single-ion model. The results show that upon nitrogenation the easy magnetization direction of PrFe_10.5Mo_1.5 changes from easy plane to easy axis. As a preliminary attempt, magnetic powders based on PrFe_10.5Mo_1.5N_x were obtained with a maximum energy product of 16.6 MGOe at room temperature. (orig.)