This article introduces the magnetic conveyor used on productionline of steel pipe and hot galvanized road protecting plate . It gives out the magnetic field design requirement of magnetic conveyor , analysis the structure characteristics of new and old magnetic route , compares the application effect of two kind of magnetic route used on galvanizing production line, and proposes the new kind of magnetic route superiority on application.

The coercivity dependence of sintered Nd-Fe-B permanent magnet alloys an orienting magnetic field was studied. The results indicate that demagnetization process of the magnet is basically the nucleation process of anti-magnetization in the soft magnetization regions located at the surface of magnetic grains，and the process in which the nuclei grow into domains and irreversible domain wall displacement takes place from the surface to the inside of grains. We compared the value and the variation dependence of nucleation field with that of depinning field on the orientation of magnetic field. we come to the conclusion that depinning field is the main mech-anism controlling the coercivity of sintered Nd-Fe-B permanent magnet alloys.

自第三代稀土永磁Nd-Fe-B合金出现以来,围绕着如何进一步提高其永磁性能,开展了许多理论及实验方面的研究工作.有些作者就其成分配方,烧结及热处理工艺进行了大量的实验探索,取得了卓有成效的成果.我们就烧结磁体制备过程中磁粉压型时的取向磁场对磁体晶粒的取向程度及其永磁性能的影响进行详细的分析、研究.

A model for the calculation of the magneto-crystalline anisotropy in R2Fe14B (R is a rare earth) compounds is presented. According to the model, a combined effect on the R-ion, coming from both the crystal field of ligands and the electric field of itinerant electrons, results in the anisotropy of the compounds. An approach of calculating the interaction between the itinerant electrons and the central R-ion is given. Taking account of the combined effect, we calculated the temperature dependences of the anisotropy of all the five R2Fe14B-type (R = Pr, Nd, Tb, Dy and Ho) compounds with uniaxial anisotropy. The results are in good agreement with the experiments. The calculation has shown that the effect of the itinerant electrons plays an important role for the anisotropy of the compounds.

The experimental results show that the coercivity of Nd-Fe-B sintermagnet decreases with increasing of the grain alignment degree of the magnets (i.e. decreasing of the orientation distribution coefficient ��). The coercivities of the magnets with different orientation degrees are calculated based on the pinning, nucleation and starting field theory, respectively. The comparison of the calculated values with the experimental results shows that the theoretical results deviate from the experiments seriously for both pinning mechanism and nucleation mechanism. In contrast with that, the calculated values based on the starting field theory are in good agreement with the experimental results.

R 2 Fe 14 B型化合物（R为稀土元素）是一类重要的磁性化合物。这类化合物的一个重要特点是具有很强的磁晶各向异性,并且随着稀土元素的不同,其磁晶各向异性表现出非常复杂的特点。关于Nd 2 Fe 14 B和Pr 2 Fe 14 B的磁晶各向异性已经有不少人采用单离子模型并对晶场取点电荷近似进行过计算,其结果只能定性或半定量地解释这两种化合物的磁晶各向异性随

I. INTRODUCTIONThe outstanding magnetic properties of Nd-Fe-B permanent alloy with very high coercive force and maximum magnetic energy product have attracted scientists’ attention greatly and extensive investigation has been made on its structure and mag-

The four stages of the demagnetization process of oriented sintered Nd-Fe-B alloy after saturation magnetizing along easy direction is studied theoretically in this paper. The results indicate that the nucleation in the soft magnetization regions located at the surface of hard magnetic grains, as well as the irreversible domain wall displacement from the surface to the inside of grains are the dominant factors controlling the intrinsic coercivity of Nd-Fe-B alloy. The rapid reduction of coercivity of Nd-Fe-B alloy with temperature rising are mainly attributed to the thermal movement of atoms it has a harmful effect on the perfection of tetragonal structure in hard magnetic grains and increases the thickness of the soft magnetization transition regions.

一、引言 具有高矫顽力及最大磁能积的Nd-Fe-B永磁合金以其优异的磁性能吸引人们就其结构、磁性开展广泛研究。现已确认,有高饱和磁化强度和强单轴各向异性的硬磁性主相Nd 2 Fe 14 B对所有Nd-Fe-B永磁体（包括不同成分配方、不同工艺过程制备的Nd-Fe-B材料）的磁性起决定性作用。因此研究并确定Nd 2 Fe 14 B的磁畴结构参量便成为研究Nd-Fe-B

c a l c u l a t i o n of t h e c o n t r i b u t i o n s of t h e c r y s t a l f i e l d ( C F ) o f n e a r e s t , n e i g h b o r s a n d n e x t n e a r e s t n e i g h b o r s t o t h e a n i s o t r o p y c o n s t a n t K i n o u r p a p e r is e r r o n e o u s . On t h a t p o i n t w e a re i n agre$ment w i t h h im. ' 2 . However, w e d o n o t a g r e e t o M r . P E I ' s a n o t h e r o p i n i o n t h a t ' t a k i n g t h e C F e x p e r i e n c e d by Fe3+ i o n s i n a-Fe2O3 as C3v sgmmetrical w a s i n c o r r e c t . I n f a c t , t h e i m a g i n a r y p a r t o f t h e CF p a r a m e t e r B 4 3 is much less t h a n t h e rea l p a r t . N e g l e c t i n g t h e i m a g i n a r y p a r t , t h e e x p r e s s i o n s ~ o f C3v c a n be u s e d a p p r o x i m a t e l y . 3 . M r . ' PE1 p o i n t e d o u t t h a t t h e e x p r e s s i o n s f o r AE(4) and A E ( 6 ) i n p a p e r (1 ) were e r r o n e o u s . A f t e r c h e c k i n g c a r e f u l l y , w e f o u n d t h a t t h e e x p r e s s i o n f o r A E ( 4 ) i n p a p e r (1 ) i s correct w h i l e ' t h a t f o r A E ( 6 ) is i n c o r r e c t . However t h e e x p r e s s i o n g i v e n b y M r . P E 1 f o r B E i n c o r r e c t . ( 4 ) is

A calculation of the magnetic single-ion anisotropy in hematite has been made. The results show that an equivalent single-ion anisotropy field Hsi (=103.8×102 Oe) exists along the c-axis at T=0K. The Morin transition in hematite could be explained by our results in conjunction with the calculated Hmd by Artman et al.

一、引言 SrF 2 和CaF 2 是具有相同晶体结构的化合物.其F -1 离子形成简立方晶格,二价金属离子占据简立方的体心。不过,其体心被占据和不被占据是彼此相间的。近十年来,关于在SrF 2 、CaF 2 中渗入稀土金属离子或3d金属离子的研究已成为一个重要课题。而近来,对