晶态合金Fe_(79)Si_7B_(14)、Fe_(83)Si_4B_(10)C_3结构弛豫的穆斯堡尔效应研究

本文应用示差热分析和穆斯堡尔谱学方法,对非晶态合金Fe_(79)Si_7B_(14)和Fe_(83)Si_4B_(10)C_3的结构弛豫过程进行了实验研究,认为其结构弛豫过程包括拓扑短程序弛豫、化学短程序弛豫和基体金属相形核长大三种形式的结构变化。     

Mssbauer study of the effect of Nb in Fe-based nanocrystalline alloy

1 INTRODUCTIONFe-based alloys with a nanocrystamne structure are very attractive soft mopeticmaterials. Especially, it has been found that nanocrystalline ajloy Feva.SCu1Nb3Si13.SBgalloy (Finemet) shows excellent magnetic properties[1'2]. The ndcrostructure of the alloys consists of ultra-ace crystalhae grains with diameter of 10-20urn and a residualamorphous phase. The relation of the ndcrostructure and the magnetic properties haseXtensively been investigated. It has been reported th…     

Er_2Fe_(17-x)Al_x(x=2,5)化合物的中子衍射研究

利用Rietveld分析方法对Er2 Fe17-xAlx(x =2 ,5)在室温下的中子衍射实验数据进行了精修。Er2 Fe15Al2 化合物具有Th2 Ni17型六角结构 ,空间群为P6 3/mmc ,Al原子分别占据 12 j(占位数0 2 1)和 12k(占位数 0 13)位 ;Er2 Fe12 Al5化合物具有Th2 Zn17型三角结构 ,空间群为R 3m ,Al原子分别占据 18f(占位数 0 35)、18h(占位数 0 36 )和 6c(占位数 0 37)位。所有的Fe原子磁矩间为铁磁性耦合。Er原子磁矩与Fe原子磁矩间为亚铁磁耦合。在 2个样品中 ,磁矩均位于垂直于六重轴的平面内 ,呈面磁晶各向异性。给出了居里温度TC,并对磁性能和结构之间的关系进行了简单的讨论。     

高温超导体EuBa_2(Cu_(1-x)Fe_x)_3O_(7-y)的穆斯堡尔谱学新研究

利用~(57)Fe和~(151)Eu穆斯堡尔效应对EuBa_2(Cu_(1-x)Fe_x)_3O_(7-y)高温超导体作了研究。在液氮温区,分别测量了样品中有和无电流通过时的~(57)Fe穆斯堡尔谱,结果表明取代了Cu(2)位置的Fe的同质异能位移和四极分裂与通过超导体的电流无关,而取代Cu(1)位置的Fe的穆斯堡尔谱参数则与电流有关。不同Fe含量样品的穆斯堡尔谱分析表明,超导电性和穆斯堡尔谱参数都与Fe的含量有关。     

Fe-(Co6Ag94)颗粒膜磁光芯片的制备及研究

采用二分掩膜技术向溅射沉积的(Co6Ag94)薄膜中组合注入Fe离子，制备成具有不同Fe含量的16单元Fe-(Co6Ag94)颗粒膜磁光芯片。对制备态和退火态的Fe-(Co6Ag94)颗粒膜的物相进行了XRD研究。不同退火温度下，物相的演变反映出了退火过程中Co、Fe相和FeCo相纳米微晶的析出长大过程。采用原子力显微镜(AFM)对薄膜表面的研究结果表明，在退火过程中形成了嵌于基底中的纳米颗粒相。对制备态和不同温度退火后芯片各单元的磁光性能进行了测量，结果表明极向Kerr旋转角晚随着注入Fe含量的增加而增大，这可归因于颗粒膜中铁磁相的增多。在500℃以下，随着退火温度的增加，Fe-(Co6Ag94)颗粒膜的克尔磁光效应增加。对不同温度退火的样品进行穆斯堡尔谱测量，结果证明一定尺寸纳米Fe微晶颗粒的出现是磁光效应提高的主要原因之一。     

用中子粉末衍射方法研究Ho2Fe17系列化合物的磁结构

在中子三轴谱仪上用中子粉末衍射方法测定了室温下样品Ａ（Ｈｏ２Ｆｅ１３Ａｌ４Ｃ）、Ｂ（Ｈｏ２Ｆｅ１３Ｇａ４Ｃ２）、Ｃ（Ｈｏ２Ｆｅ９Ｇａ４Ａｌ４）和Ｄ（Ｈｏ２Ｆｅ９Ｇａ６Ａｌ２）的晶体结构和磁结构。衍射数据用Ｉｚｕｍｉ的Ｒｉｅｔｖｅｌｄ分析程序ＲＩＥＴＡＮ进行轮廓精修处理，确定了替代原子Ｇａ、Ａｌ和间隙原子Ｃ的占位及占位数以及磁性原子Ｈｏ、Ｆｅ的原子磁矩的大小和方向。样品Ａ、Ｂ和Ｄ显亚铁磁性，Ｃ显顺磁     

Magnetovolume and chemical bonding effects of Sn atom in the γ'-(Fe1-xSnx)4N compounds

Combining x-ray diffraction and high pressure Mossbauer spectroscopy,the structure and the hyperfine parameters of Sn substituted for Fe in γ'-Fe4N were in-vestigated. The results of x-ray diffraction indicate that single phase γ'-(Fel-xSnx)4Ncompounds can be synthesized in the composition range 0≤ x ≤ 0.3, and the latticeparameter can be well fitted with two linear formulas α0(x) = 3.795 + 0.019 × x (0.0≤x ≤0.10) and α0(x) = 3.795+ 0.228 × (x- 0.1)(0.10 ≤ x ≤0.30) for different contentof Sn. Using high pressure Mossbauer spectra, the influences of the magnetovolunceffect and the chemical bonding effect of Sn atom on the hyperfine magnetic field andthe isomer shift were first distinguished. It is found that the magnetovolume and thechemical bonding have different influences on the properties of γ'-(Fe1-xSnx)4N, andthe latter plays a more important role.     

新型微晶软磁合金Fe_(73.1)Cu_(1.2)Nb_(3.2)Si_(12.5)B_(10)显微组织的穆斯堡尔研究

运用穆斯堡尔效应的方法考查了原始制备态和退火态的Fe_(73.1)Cu_(1.2)Nb_(3.2)Si_(12.5)B_(10)合金的显微组织。计算表明:退火的具有超细晶粒的微晶合金的显微组织主要由主晶相Fe_(75+y)Si_(25-y)型有序相和非晶态晶界相组成,可能含有很少量的顺磁相。组织中主相Fe_(75+y)Si_(25-y)含量大约为70％,非晶相约为26％。有序相Fe_(75+y)Si_(25-y)中的y在5—7之间。     

钴基非晶合金的穆斯堡尔研究

非晶合金可以用不同的方法制备,本文所论及的金属-类金属非晶合金是用熔融态合金快速淬冷来制备的。为了研究非晶合金Co_(74.5)~(57)Fe_(0.5)B_(25-x)M_x(其中M=Ge、Si、C)的结构和热性质,我们用穆斯堡尔谱仪和示差热扫描仪(简称DSC仪)进行测量分析。     

用中子衍射研究稀土-富铁永磁合金磁结构和D(H)LAP晶体结构

用粉末中子衍射测量Ｈｏ２Ｆｅ９Ｇａ８－ｘＡｌｘ（ｘ＝２,４）和ＰｒＦｅ１０．５Ｍｏ１．５Ｎｘ的晶体结构和磁结构。衍射数据分别用ＲＸｉｅｔｖｅｌｄ结构精修程序ＲＩＥＴＡＮ和Ｆｕｌｌｐｒｏｆ处理。确定了替代原子Ｇａ,Ａｌ,Ｍｏ及间隙原子Ｎ的占位数以及磁性原子Ｈｏ,Ｆｅ,Ｐｒ的原子磁矩的大小和方向。     

Neutron diffraction study of Er2Fe15A12 and Er2Fe12A15

The crystallographic and magnetic structures of Er2Fe15Al2 and Er2Fe12Al5 have been refined in Gaussian peak-shape by Rietveld analysis of Neutron diffraction data. The refined results indicated that Er2Fe15Al2 compound has Th2Ni17-typc hexagonal structure (space group: P63/mmc) and Er2Fe12Al5 has Th2Zn17-type rhombohedral structure (space group:R 3m). The Al atoms prefer 12j and 12k sites with ccupancies 0.21 and 0.13, respectively, in Er2Fe15Al2 and prefer 18f, 18h and 6c sites with occupancies 0.35, 0.36 and 0.37, respectively, in Er2Fe12Al5. The magnetic moments of all Fe atoms display ferromagnetically arrangement and the moments of Er atoms couple ferrimagnetically to the moments of the Fe atoms. The moments lie in the plane perpendicular to the six-fold axis and exhibit planar magnetic anisotropy in both samples. The values of Tc were given and the neutron refined results coincide with that of the magnetic measurements. The relation between magnetic properties and structures was discussed.     

铕钆铁氧体Eu1—xGdxFeO3的穆斯堡尔谱学研究

合成了铕钆铁氧体Eu_(1-x)Gd_xFeO_3(x分别是0.2,0.4,0.6,0.8)。用X光衍射方法分析这些化合物的结构,结果表明都是正交钙钛矿结构。用~(151)Eu和~(57)Fe两种穆斯堡尔谱来研究所合成样品的微观结构,得到的~(131)Eu谱是纯四极相互作用谱,分解实验谱得到的同质异能位移参数和四极分裂参数都随x不同而变化。类似地,Fe谱的超精细场参数和样品的晶胞体积线性相关。另外,直接用高温高压方法合成的样品有部分顺磁相存在。     

MSSBAUER EFFECT STUDY OF MAGNETIC INTERACTIONS IN Eu(Fe_(0.8)M_(0.2))O_3 (M=Sc, Cr, Mn, Co)

The solid state solutions of europium transition element oxides Eu (Fe0.8M0.2)O3 (M=Sc, Cr, Mn, Co) are synthesized. The X-ray diffraction of the compound shows that all the compounds possess the perovskite structures. Both the 151Eu Mossbauer spectra and the Fe Mossbauer spectra are measured. The hyperfine magnetic field and non-axisymmetric electric field gradient are observed in the Eu Mossbauer spectrum. The 57Fe Mossbauer spectrum shows that there are four components of hyperfine fields corresponding to four kinds of different neighbours of the Fe ion.     

Neutron diffraction study of Er_2Fe_(15)Al_2 and Er_2Fe_(12)Al_5

The crystallographic and magnetic structures of Er2Fe15Al2 and Er2Fe12Al5 have been refined in Gaussian peak-shape by Rietveld analysis of Neutron diffraction data.The refined results indicated that Er2Fe15Al2 compound has Th2Ni17-type hexagonal structure (space group:P6 3/mmc) and Er2Fe12Al5 has Th2Zn17-type rhombohedral structure (space group:R3m),The Al atoms prefer 12j and 12k sites with occupancies 0.21 and 0.13 ,respectively,in Er2Fe15Al2 and prefer 18f,18h and 6c sites with occupancies 0.35,0.36 and 0.37,respectively ,in Er2Fe12Al5,The magnetic moments of all Fe atoms display ferromagnetically arrangement and the moments of Eratoms couple ferrimagnetically to the moments of the Fe atoms .The moments lie in the plane perpendicular to the six-fold axis and exhibit planar magnetic anisotropy in both samples,The values of Tc were given and the neutron refined results coincide with that of the magnetic measurements .The relation between magnetic properties and structures was discussed.     

Er2Fe17—xAlx（x=2,5）化合物的中子衍射研究

利用Rietveld分析方法对Er2Fe17-xAlx(x=2,5)在室温下的中子衍射数据进行了精修。Er2Fe15Al2化合物具有Th2Ni17型六角结构,空间群为P63／mmc,Al原子分别占据12j(占位数0．21）和12k(占位数0.13)位;Er2Fe12Al5化合物具有Th2Zn17型三角结构,空间群为R3m,Al原子分别占据18f(占位数0．35）、18h(占位数0．36）和6c(占位数0．37）位。所有的Fe原子磁矩间为铁磁性耦合。Er原子磁矩与Fe原子磁矩间为亚铁磁耦合。在2个样品中,磁矩均位于垂直于六重轴的平面内,呈面磁晶各向异性。给出了居里温度Tc,并对磁性能和结构之间的关系进行了简单的讨论。     

用离子注入法制备~(57)Fe穆斯堡尔样品

~(57)Fe是在常温下就能测量穆斯堡尔谱的最常用和方便的同位素之一。应用同位素分离器把~(57)Fe同位素注入待测样品,然后测量样品中~(57)Fe受激发后的内转换电子(或X,γ射线)的穆斯堡尔谱,这是近年来己发展起来的一种新的穆斯堡尔实验技术。由于它可以对不含有穆斯堡尔核素的样品进行所需穆斯堡尔核素的离子注入,并可对样品进行非破坏性测量,从而扩大了穆斯堡尔效应的应用范围。     

RFe10V2（R=Y,Er）的穆斯堡尔谱研究

通过对ＹＦｅ１０Ｖ２中铁晶位配位情况的详细分析，提出在具有ＴｈＭｎ１２结构的稀土－过渡金属间化合物中，铁晶位超精细场指认的一般方法。结合点电荷和有效价键模型，对ＲＦｅ１０Ｖｗ的穆斯堡尔谱进行了研究。