r annealing has great dependences on the interpore distance and the wire diameter. The model of the prolate ellipsoid chain modified with the magnetostatic interaction is employed to explain this geometry dependence of the annealing effect. After annealing at 550℃ in H2 atmosphere, good hard magnetic properties (at room temperature, coercivity Hc=3.89 kOe, squareness Mr/Ms=0.954; at 78 K, Hc=4.55 kOe, Mr/Ms=0.954) were obtained in the arrays with a diameter of about 22 nm and an interpore distance of about 50 nm.

A nonequilibrium phase transformation in a stoichiometric NdFe11Ti compound during mechanical milling was monitored by the measurements of AC susceptibility, magnetization, X-ray di

A nonequilibrium phase transformation in a stoichiometric NdFe11Ti compound during mechanical milling was monitored by the measurements of AC susceptibility, magnetization, X-ray di

We have succeeded in synthesizing PrFe11V12xTix (x50.2-1) compound and their nitrides with the ThMn12-type structure. The phase formation and magnetic properties have been investigated by x-ray diffraction, differential thermometric analysis, and magnetic measurement. The stable temperature range of the 1-12 phase for PrFe11V12xTix alloys has been determined as a function of Ti content. PrFe11V compounds with the ThMn12-type structure do not exist and PrFe11Ti compounds with the TnMn12-type structure are obtained by annealing in a narrow temperature range between 1303 and 1383 K. Furthermore, 1-12 phase with the ThMn12-type structure can be obtained at lower temperature and wider temperature range with decreasing Ti content x (0.2<x<1). PrFe11V12xTixNy with x50.2-1 has a Tc of about 730-785K, Ba larger than 8 T and Ms in the range 144-148 emu/g. These intrinsic magnetic properties are highly favorable for permanent magnet applications. As a preliminary, an intrinsic coercivity of 5.4 kOe is obtained for PrFe11V0.5Ti0.5Ny at room temperature by using mechanical alloying technique.

Phase formation in annealed mechanical alloyed NdFe V Ti, and magnetic properties of the consequent phases and their 10.51+x1.5 (1-x)Tix nitrides were investigated by using X-ray diffraction and magnetic measurement. From the X-ray diffraction patterns we have constructed a phase formation diagram as a function of Ti content x and annealing temperature. The demarcation curve between 1:7 and 1:12 phases moves to higher annealing temperatures with increasing Ti content. In the NdFe Ti alloy the ThMn structure is obtained by annealing 11:12 the as-milled powder at temperatures above 950℃. The nitrides NdFe V Ti N retain the same structure as their parent 10.5+0.5xV1.5 (1+x) compounds. The nitride with high V content is more stable than that with low V content. Upon nitrogenation, the Curie temperature is enhanced from 150℃ to 180℃. In NdFe V Ti N T the values fall in the range 450～480℃. The hard magnetic properties 10.5+0.5xV1.5 (1-x)TixNy magnets have been assessed.