R3（Fe,Mo）29（R=Sm,Y）化合物及其氮化物的磁性

合成了Ｒ３（Ｆｅ,Ｍｏ）２９（Ｒ＝Ｓｍ,Ｙ）化合物并在０．１ＭＰａ氮气条件下通过气相氮化法制备出其氮化物。Ｒ３（Ｆｅ,Ｍｏ）２９金属间化合物氮化后仍保持母相结构,但是晶胞体积发生膨胀,氮化处理同时导致化合物居里温度Ｔｃ和饱和磁化强度σｓ升高同时Ｓｍ３（Ｆｅ,Ｍｏ）２９化合物由平面各向异性变为单轴各向异性,但Ｙ３（Ｆｅ,Ｍｏ）２９Ｎｘ化合物的各向异性仍与母相相同,为面各向异性。     

Ga替代对Gd2（Fe,Co）17化合物磁性的影响

通过Ｘ射线衍射和磁性测量手段研究了Ｇｄ２（Ｆｅ０．８Ｃｏ０．２）１７－ｘＧａｘ（０≤Ｘ≤８）化合物的结构和磁性。实验结果表明Ｇｄ２（Ｆｅ０．８Ｃｏ０．２）１７－ＸＣａＸ化合物均为菱方的Ｔｈ２Ｚｎ１７型结构,单胞体积Ｖ随Ｃａ含量的增加单调上升,居里温度Ｔｃ和饱和磁化强度Ｍｓ随Ｇａ含量的增加而单调下降。粉末取向样品的Ｘ射线衍射结果表明,随Ｇａ含量的增加,化合物的室温易磁化方向由易面转变为易轴,Ｇｄ２（Ｆｅ．８Ｃｏ０．２）１７－ＸＣａＸ化合物的３ｄ亚晶格出现室温单轴各向异性可能与Ｃａ原子的择优占位有关。     

Sm2（Fe,Ga）17Cy的结构与磁性

在２：１７型稀土－铁－碳化物中，用Ｇａ替代Ｆｅ，可稳定稀土碳化物的晶体结构。本文讨论了Ｓｍ２Ｆｅ１７－ｘＧａｘＣｙ（２≤ｘ≤６，０≤ｙ≤３．０）化合物的形成。结果与磁性，给出了单胞体积Ｖ，室温饱和磁化强度σｓ居里温度Ｔｃ和室温各向异性场Ｈａ与Ｃａ和Ｃ含量的关系，发现在低Ｇａ和高Ｃ样品中，居里温度一般大于６２０Ｋ，室温各向异性场高于１２０ＫＯｅ，快淬方法获得在室温轿顽力大于１３ＫＯｅ。     

R3（Fe,M）29化合物中的Fe—Fe及R—Fe之间的交换作用

根据Ｒ３（Ｆｅ，Ｍ）２９（Ｒ＝稀土，Ｍ＝Ｖ、Ｔｉ、Ｍｏ）化合物的居里温度的实验值，使用平均场近似的方法计算Ｒ３（Ｆｅ，Ｍ）２９化合物中的Ｒ－Ｆｅ，Ｆｅ－Ｆｅ之间的交换耦合参数ＪＲＦｅ和ＪＦｅＦｅ。结果表明：对于Ｒ相同而Ｍ不同时，当Ｍ＝Ｖ时ＪＦｅＦｅ最大，而Ｍ＝Ｍｏ时ＪＦｅＦｅ最小；但是，当Ｍ＝Ｔｉ时ＪＲＦｅ最大，当Ｍ＝Ｍｏ时ＪＲＦｅ最小。     

La_1－zRz（Fe_1－x－yCoxAly）_（13）金属间化合物磁熵变特性研究

本文对用Ｆｅ、Ａｌ替代Ｃｏ的Ｌａ（Ｆｅ（０．７３）－ｘＣｏｘＡｌ（０．２７））（１３）系和用Ｒ（Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｄｙ，Ｇｄ）替代Ｌａ的Ｌａ１－ｚＲｚ（Ｆｅ（０．７１）Ｃｏ（０．０２）Ａｌ（０．２７））（１３）系的结构、磁性及磁熵变特性进行了研究。实验发现，Ｌａ（Ｆｅ（０．７８）－ｘＣｏｘＡｌ（０．２７））（１３）系的晶体结构均保持ＬａＣｏ（１３）的立方结构，每３ｄ原子的饱和磁矩与其电子数ｎｄ的关系在富Ｃｏ侧符合刚性能带模型，而在富Ｆｅ侧则与该模型不符。当ｘ＝０．０２时该化合物的居里温度在室温并有较高的磁熵变△ＳＭ，在１．１１ＭＡ／ｍ（１．４Ｔ）磁场下的（△ＳＭ）ｍａｘ为１３ｋＪ／ｍ３·Ｋ。对于Ｌａ１－ｚＲｚ（Ｆｅ（０．７１）Ｃｏ（０．０２）Ａｌ（０．２７））（１３）系，实验发现除Ｃｅ外，其它稀土元素均不能与Ｌａ、Ｆｅ、Ｃｏ、Ａｌ形成１：１３相，而是形成了２：１７相。     

Sm2（Fe1—xCrx）17N～2.7永磁材料的结构与磁性能

研究了Ｃｒ部分取代Ｆｅ对Ｓｍ２（Ｆｅ１－ｘＣｒｘ）１７Ｎ～２．７磁粉磁特性的影响。添加少量Ｃｒ（ｘ＝０－０．１），该化合物的结构不变化。随Ｃｅ含量的增加，它的Ｃｕｒｉｅ温度、各向异性场饱和磁化强度、平均Ｆｅ原子磁矩和平均超精细场均有所降低。材料的单相性显著改善，矫顽力提高。Ｓｍ２（Ｆｅ０．９５Ｃｒ０．０５）１７Ｎ～２．７磁粉的矫顽力ｉＨｃ达到１５９２ｋＡ／ｍ。     

体状Fe3N和Fe2N化合物合成及其磁特性研究

纯铁粉在一定比例的氨和氢的气氛中,在某一温度下铁和氮进行固气反应。研究了氨气和氢气的比例对固气反应产物的影响规律;温度和时间对反应产物的影响规律,进而获得单一均匀的体状Ｆｅ３Ｎ和Ｆｅ２Ｎ化合物。利用振动样品磁强计、磁天平和热磁分析等手段检测了Ｆｅ３Ｎ和Ｆｅ２Ｎ的磁特性。Ｆｅ３Ｎ化合物的饱和磁化强度（室温）为１３４Ａｍ２／ｋｇ,居里温度Ｔｃ＝２６０℃;而Ｆｅ２Ｎ化合物饱和磁化强度为２３．１Ａｍ２ｋｇ,属于弱磁性和非磁性,居里温度Ｔｃ＝２５℃。     

快速凝固（Sm1—xBx）Fe2合金的结构和磁性

采用真空单辊快淬法（铜辊,线速度达２０～２３ｍ／ｓ）将成分为（Ｓｍ１－ｘＢｘ）Ｆｅ２（ｘ＝０,０．０１５,０．０３,０．０４５,０．０６）合金锭,制成快速凝固的鳞片状合金,再经粉碎在３０ＭＰａ压力下,模压成φ１０ｍｍ圆片,然后进行ＸＲＤ分析,比磁化强度和磁致伸缩（λ″－λ┴）的测量。实验结果表明各样品只有少量非晶相,主要是ＳｍＦｅ２及少量的ＳｍＦｅ５和ＳｍＦｅ７化合物。样品（Ｓｍ０．９８５Ｂ０．０１５）Ｆｅ２和（Ｓｍ０．９４Ｂ０．０６）Ｆｅ２,在７２０ｋＡ／ｍ磁场下,比磁化强度分别为：５９．５,５２．３Ａｍ２ｋｇ－１,在８８５ｋＡ／ｍ磁场下（λ″－λ┴）分别为：－５１０×１０－６和－３１０×１０－６。     

SmFe10.7—xMo1.3Gax化合物的结构与内禀磁性

本文详细研究了Ｇａ取代Ｓｍ（Ｆｅ,Ｍｏ）１２化合物中的部分Ｆｅ对其结构和内禀磁性的影响。     

YTi（Fe_（1－x）Co_x）_（11）的化学法合成及其结构、磁性能

应用共沉淀－还原扩散法成功地合成了ＹＴｉ（Ｆｅ（１－ｘ）ＣＯｘ）（１１）系列稀土永磁合金（ｘ＝０．０，０．１５，０．２５，０．５），确定了其最佳合成条件，采用ＸＲＤ研究了其晶体结构及在Ｍ１５５型振动样品磁强计上测了其居里温度和磁化强度。得出：ＹＴｉ（Ｆｅ（１－ｘ）ＣＯｘ）（１１）系列合金均具有ＴｈＭｎ（１２）型结构，其晶胞参数随Ｃｏ掺入量增大而减小；居里温度点随Ｃｏ掺入量增大而升高；比饱和磁化强度在ｘ＝０．１５处达到最大。     

MAGNETIC PROPERTIES OF R 3(Fe, Mo) 29 N x (R=Sm OR Y) INTERSTITIAL NITRIDES

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＲ３（Ｆｅ,Ｍ）２９（Ｒ＝ｒａｒｅｅａｒｔｈ;Ｍ＝Ｔｉ,Ｖ,Ｍｎ,Ｍｏ,ｅｔｃ）ｃｏｍｐｏｕｎｄｓａｒｅｎｅｗｌｙｄｉｓｃｏｖｅｒｅｄｒａｒｅｅａｒｔｈｉｒｏｎｉｎｔｅｒｍｅｔａｌｉｃｓ．Ｔｈｅｙａｌｍｏｓｔｅｘｉｓｔ...     

Nd3（Fe,Mo）29化合物及其氮化物的磁结构和内禀磁性

制备了具有Nd3（Fe,Ti）29型单斜结构的单相铁基金属间化合物Nd3（Fe,Mo）29及其氮化物,详细研究了：其在4．2K～300K之间的磁结构;磁晶各向异性;居里温度Tc,饱和磁化强度σs等内禀磁性。研究结果表明：Nd3（Fe,Mo）29金属间化合物氮化后仍保持母相结构,氮化后的晶胞体积,居里温度Tc和饱和磁化强度σs分别比氮化前提高了5．9％,70．9％,6．6％;N3d（Fe,Mo）29金属间化合物在230K左右存在自族重取向,温度低于230K时,其磁晶各向异性为锥面,温度高于230K时,其磁晶各向异性为易面;氮化后自族重取向消失。     

Sm_2Co_(17-x)Ti_x化合物的结构和磁性

利用 Ｘ射线衍射和磁性测量研究了 Ｓｍ２Ｃｏ１７－ｘＴｉｘ化合物的结构和磁性实验表明这些化合物都具有 Ｔｈ２Ｚｎ１７型 结构, Ｔｉ替代 Ｃｏ不改变化合物的晶体结构,但引起晶格膨胀所有化合物在 Ｃｕｒｉｅ温度以下都表现为单轴磁晶各向异性随 着 Ｔｉ含量的增加,化合物的 Ｃｕｒｉｅ温度和饱和磁化强度都单调降低,而磁晶各向异性场在 Ｔｉ含量为 １．０时出现一极大值     

Structural and magnetic properties of (Sm_0.5Nd_0.5)_2(Fe_(1-x)Co_x)_(17)compounds

The structure, magnetization, and magnetocrystalline anisotropy were investigated using X-ray diffraction, vibrating sample magnetometer, and AC susceptibility-meter. It is found that the microstructure of (Sm0.5Nd0.5)2(Fe1-xCox)17 alloys is an (Sm,Nd)2(Fe,Co)17 phase with the rhombohedral Th2Zn17-type structure. The Curie temperature Tc increases with the Co concentration increasing, and the magnetization first increases as the Co content increases in (Sm0.5Nd0.5)2(Fe1-xCox)17 alloys and then decreases slowly. The easy magnetization direction (EMD) of (Sm0.5Nd0.5)2(Fe0.25Co0.75)17 is along the c-axis and a strong enhancement of the crystalline anisotropy energy constant K is produced by the addition of some Co atoms. The anisotropy energy constant reaches the maximum when x = 0.75 and then decreases slowly with the Co content further increasing. The (Sm0.5Nd0.5)2(Fe0.25Co0.75)17compound is an optical candidate for the new permanent magnet, which possesses a high magnetization, a high Curie temperature,     

EFFECTS OF Al CONTENT ON STRUCTURAL STABILITY AND MAGNETIC PROPERTIES OF Sm2 (Fe, Al) 17 COMPOUNDS

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔＳｍ２Ｆｅ１７Ｎｙｃｏｍｐｏｕｎｄｓｈａｖｅｇｏｏｄｉｎｔｒｉｎｓｉｃｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓ［１］．ＢｅｃａｕｓｅｏｆｔｈｅｐｏｏｒｓｔａｂｉｌｉｔｙｏｆＳｍ２Ｆｅ１７Ｎｙａｔ...     

Magnetocrystalline anisotropy and exchange interactions in the novel R3(Fe, V)29 compounds (R = Y, Nd, Sm)

A type of magnetocrystalline anisotropy and exchange interactions of the novel ternary R₃(Fe, V)₂₉ compounds (R = Y, Nd, Sm) have been investigated. The compounds are uniaxial ferromagnets with easy magnetization direction along the [ 0 1] axis of the monoclinic lattice at room temperature. The temperature variations of the magnetic moment and the first anisotropy constant for Y₃(Fe, V)₂₉ are presented. The first order magnetization process along the hard magnetization direction takes place for Sm₃(Fe, V)₂₉ at T < 120 K. A magnetic anomaly is detected in the temperature dependence of the a.c. susceptibility for Nd₃(Fe, V)₂₉ which can be related to a spin reorientation.     

稀土材料La—Ba—（Mn,Fe）—O的磁电输运特性探讨

研究制备了Ｌａ０．６７Ｂａ０．３３Ｍｎ１－ｘＦｅｘＯ３（ｘ＝０,０．０５,０．１）材料。结果表明：铁替换锰降低了材料的饱和磁化强度及居里温度,主要是因为Ｆｅ离子不参加双交换作用,同时Ｍｎ＾３＋－Ｏ＾３－Ｍｎ＾４＋的作用对随铁离子替代Ｍｎ＾３＋而数量减少,材料的铁磁作用随之减弱。铁替换降低了金属－半导体转换峰温度,相应提高了材料的零场电阻值。值得注意的是铁掺杂提高了大磁阻材料Ｌａ０．６７Ｂａ０．３３Ｍｎ１－ｘＦｅｘＯ３的低温性能,５Ｋ下磁阻比「Ｒ（６Ｔ）－Ｒ（０）」Ｒ（０）从ｘ＝０时的－４０％增加到ｘ＝０．１时的－６０％。本文同时利用迪尼模型对材料大磁阻效应进行了计算分析,发现理论计算曲线可以较好的反映实验上出现的金属－半导体转换峰现象,同时负的大磁阻效应现象也可从理论计算上得到证实。     

MAGNETIC PROPERTIES OF Nd_2(Fe_(1-x)M_x)_(14)B(M=C,Si)ALLOYS

The magnetic properties of Nd_2(Fe_(1-x)M_x)_(14)B(M=C and Si) compounds have been investi-gated.Substituting Fe by small amount of metalloid C and Si atoms,the compounds are intetragonal structure and have uniaxial anisotropy.The substitution of C for part of Fe de-creases the Curie temperature of the compounds and the intrinsic coercivity of bond samples atlow temperature.The replacement of Fe by Si makes the Curie temperature increase with amaximum at the vicinity of x=0.15.When the range of the content of Si is 0≤x≤0.10,thecoercivity distinctly increases at room temperature.from 62.7 kA/m at x=0 to138.7kA/m at x=0.06,where the residual magnetization has a maximum:in the mean timethe saturation magnetization decreases only by a small amount.     

STRUCTURE AND MAGNETIC PROPERTIES OF YFe12-xTix COMPOUNDS

1. IntroductionThe discovery of NdZFe14B compound['1 hAs not only led to the appearance of thethird generation of rare-earth permanellt magnets, but also stimulated many researchersto search for novel iron-rich rarerearth ilitermetallic compounds with permanent magnetproperties. In the last decade, investigation of magnetic and structural properties of therare earth (R) transitional metal (T) intermetallic compounds and their nitrides withThMn12-type structure became one of focal points in …     

Peculiarities of the R3(Fe,Si)29 phase formation in the Sm---Fe---Si system

The phase content of the Sm(Fe_1−xSi_x)_y alloys (0.05≤x≤0.15; 8.5≤y≤12) has been studied by X-ray diffraction using micromonocrystals. The compounds Sm₂(Fe,Si)₁₇, Sm(Fe,Si)₁₂ and a novel Sm₃(Fe,Si)₂₉ compound with a monoclinic unit cell are found. The lattice parameters of Sm₃(Fe,Si)₂₉ are: a=1.056 nm, b=0.850 nm, c=0.966 nm, β=96.8°. This compound forms as a result of a solid state transformation from the high-temperature Sm₂(Fe,Si)₁₇ phase. Diffuse effects observed in rocking photographs suggest transition structures arising from this transformation. The Curie temperatures of Sm₃(Fe,Si)₂₉ vary in the interval 496–521 K.