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Structural and magnetic properties of R2Fe14-xMxB systems (R = Y, Gd, M = Si, Cr, Cu) are investigated. These compounds crystallize in a tetragonal system at P42/mnm-type for a Si content up to x = 2, Cr content up to x = 3 and for Cu concentration up to x = 1.5. The Curie temperature increases when Fe is substituted by Si and Cu, decreases when Fe is replaced by Cr. The saturation magnetization decreases with increasing content of a M element.

The results of structural and magnetic properties performed on R2Fe14−xNixB (R Nd, Gd) alloys are presented. These compounds are homogeneous up to x ⪆ 3 and crystallize in a tetragonal system of P4/mnm-type. With substitution of Fe by Ni, the saturation moments and anisotropy fields decrease, but the Curie temperatures increase significantly. The influence of Ni atoms on the spinreorientation temperature is discussed. Es werden die strukturellen und magnetischen Eigenschaften von R2Fe14−xNixB-Legierungen (R Nd, Gd) untersucht. Diese intermetallischen Verbindungen sind homogen bis zu x ⪆ 3. Sie kristallisieren im tetragonalen System vom P4/mnm-Typ. Die Sattigungsmagnetisierung und das Anisotropiefeld sinken mit steigendem x, die Curie-Temperatur wachst jedoch bedeutend. Es wird der Einflus der Nickelatome auf die Spin-Reorientierungstemperatur diskutiert.

Azoles. 22. 1H- and 13C-N.M.R. Investigation of Isomeric-3 and 5-Amino-Pyrazole Derivatives The 1H- and 13C-n.m.r. spectra of nine pairs of isomeric 3- and 5-amino-pyrazole derivatives 1a—1i and 2a—2i and some of their acetylderivatives have been assigned and discussed. It has been found that 1H- and 13C-n.m.r. spectroscopy is a useful tool for differentation of the above mentioned 3- and 5-amino-isomers.

Properties of amorphous SmxFe80−xB20 ribbons are investigated. Saturation magnetization and Curie temperature decrease whereas the crystallization temperature increases with increasing samarium content. Saturation magnetostriction varies from 37 × 10−6 for x = 1 to 12 × 10−6 for x = 9. The coercivity decreases with decreasing magnetostriction. The domain structure is also studied. Es werden die Eigenschaften der amorphen Legierung SmxFe80−xB20 untersucht. Die Sattigungsmagnetisierung und Curie-Temperatur fallen und die Kristallisationstemperatur wachst mit x. Die Sattigungsmagnetostriktion variiert. von 37 × 10−6 fur x = 1 bis 12 × 10−6 fur x = 9. Die Koerzitivkraft verringert sich, wenn die Magnetostriktion kleiner wird. Es wird auch die Bereichstruktur untersucht.

Etude realisee pour 0≤x≤8. Influence de la teneur en Ho sur le point de Curie et la temperature de cristallisation

Magnetic measurement, are performed on R2Fe14–xCrxB compounds (R = Y, Nd, and Gd). These compounds, crystallize in the Nd2Fe14B structure up to x ≦ 3. The Curie temperature and the lattice constants a and c decrease with increasing Cr content. The spin-reorientation temperature in Nd2Fe14B is lowered when Cr replaces partially Fe. The influence of Cr atoms on the anisotropy field and the saturation magnetization is discussed. Es werden magnetische Messungen an R2Fe14–xCrxB-Verbindungen (R = Y, Nd und Gd) durchgefuhrt. Diese Verbindungen kristallisieren in der Nd2Fe14B-Struktur bis x ≦ 3. Die Curie-Temperature und die gitterkonstanten a und c verringern sich mit dem Wachsen des Cr-Gehaltes. Die Spinreorientierungstemperatur in Nd2Fe14B nimmt ab, wenn Cr teilweise Fe ersetzt. Es wird der Einflus der Cr-Atome auf das Anisotropiefeld und die Sattigungsmagnetisierung diskutiert.

The results of magnetic and structural measurements performed on the Nd 2 Fe 14- x Nb x B and Nd 2 Fe 12- x Nb x Co 2 B compounds with 0 ⪅ x ⪅ 0.5 are presented. All the compounds studied crystallize in the tetragonal Nd 2 Fe 14 B structure. The saturation moments decrease by introducing Nb. The rate of the decrease is larger than that expected by a simple dilution model. The Curie temperatures and anisotropy fields are found to increase. Thus a small amount of Nb incorporated into Nd 2 Fe 12 Co 2 B may benefit this material for permanent magnet fabrication.

The structural and magnetic properties of RFe 10 Si 2 , R=Y, Gd, Tb, Dy, Ho, Er, Tm, are investigated. X-ray diffraction shows that these materials crystallize in the tetragonal ThMn 12 structure. The Curie temperatures vary in the range from 535 to 613 K. Saturation magnetization at 77 and 295 K and the anisotropy field at 295 K are determined. The spin-reorientation phase transitions are investigated in the range from 77 K to room temperature. The mean field approximation was applied to establish intra- (Fe-Fe) and intersublattice (R-Fe) exchange interactions. The properties of these compounds are compared with those of R 2 Fe 14 B alloys.

Cristallisation dans le systeme monoclinique, groupe P2 1 et affinement jusqu'a R=0,070. La molecule est constituee de 5 cycles a 6 chainons. Fusion cis des cycles D et E et conformation sofa legerement deformee du cycle C

The 13C NMR spectra of five pairs of 18β- and 18°-11-oxooleanolic acid derivatives have been assigned. The chemical shifts of C-12, C-13, C-17, C-18 and C-28 are of diagnostic value for the determination of the D/E junction stereochemistry.

The mass spectral fragmentation of five pairs of 18β- and 18α-11-oxooleanolic acid derivatives 1a, 1b–5a, 5b are investigated and discussed. Fragmentation pathways, elucidation of which were assisted by accurate mass measurements and metastable transitions, are proposed, The obtained data create a safe basis for distinguishing the above-mentioned 18 diastereomers.

The experimental values of Curie temperatures of RFe12−xTx (R = rare earth, T = V, Ti, Si, Cr) are used to calculate the effective exchange coupling constants in iron sublattice and between rare earth and iron sublattices. A mean field approximation is used. Values of molecular field, Bmol, acting on the rare earth ion are also established. The coupling constant in Fe sublattice is found to be the largest for T = V; JFeFe = 10.14 × 10−22 J. The molecular field has its maximum value for R = Sm in each series of RFe12−xTx compounds. Die experimentellen Werte der Curie-Temperaturen der intermetallischen RFe12−xTx (R = seltene Erde, T = V, Ti, Si, Cr)-Verbindungen werden benutzt, um die effektiven Wechselwirkungskonstanten im Fe-Untergitter und zwischen den R- und Fe-Untergittern zu berechnen. Es wird eine Mittelfeldnaherung angewendet. Die Grosen der Molekularfelder, Bmol, welche auf die Ionen der seltenen Erden einwirken, werden auch angegeben. Die Kopplungskonstante im Fe-Untergitter hat den grosten Wert in Verbindungen mit T = V, JFeFe = 10,14 × 10−22 J. In allen T-Serien der Verbindungen RFe12−xTx hat das Molekularfeld seinen maximalen Wert fur R = Sm.

Mir der Methode der Bitterschen Streifen wurde der Einflus des auseren Magnetfeldes auf die Entstehung von Bereichsstrukturen in Mn5Ge3 untersucht. Beim Abkuhlen unter die Curie-Temperatur in einem auseren Magnetfeld erhalt man an Stelle der schon fur diese intermetallische Verbindung bekannten „Maandermuster” eine Honigwabenstruktur. Eine Anderung erfahrt auch die Bereichsstruktur nach dem Aufmagnetisieren bis zur Sattigung und Abschalten des auseren Magnetfeldes.

Die Abhangigkeit der Maander-, Wurm- und Wabenstruktur von der Kristalldicke T (parallel zur magnetischen Vorzugsachse), bei der eine Oberflachenstruktur auftritt, wurde fur die intermetallische Verbindung Mn5Ge3 untersucht. Es wurde gefunden, das innerhalb der gemessenen Kristalldicken (40 bis 900 μm) die Bereichsbreite und die Entfernung zwischen den Mittelpunkten zweier benachbarter Wabenzellen proportional zu T2/3 ist. Diese Beziehung stimmt mit der Theorie von Kaczer und fruheren Messungen an Magnetoplumbit und Kobalt uberein.

The transverse magnetoresistance of Ho x Co 70- x B 30 amorphous ribbons in the composition range 0⪕ x ⪕8 was measured in pulsed magnetic fields up to 22 T. A positive contribution to the magnetoresistance was found in all investigated alloys. The results are interpreted in terms of the band model of magnetism and antiferromagnetic RE-3d exchange interactions.

The Sm 2 (Co 1-x Ag x ) 17 alloys in the concentration range 0 \leq x \leq 0.07 have been studied. The unit cell volume is found to increase by introducing Ag. The saturation magnetization monotonically decreases with x . The anisotropy constant K 1 at room temperature increases from 3.2J/cm3for Sm 2 Co 17 to 6.2 J/cm3for Sm 2 (Co 0.97 Ag 0.03 ) 17 . A small amount of Ag incorporated to Sm 2 Co 17 significantly beneficiates this material for permanent magnets fabrication.

Structural and magnetic characteristics of R2Fe14-xCuxB systems (R = Y, Nd and Gd) have been investigated. These compounds crystallize in a tetragonal system of P42/mnm-type for a Cu content up to x⩽1.5. The Curie temperature and lattice parameters a and c increase with substitution of Fe by Cu. The spin-reorientation temperature in the Nd2Fe14B compound is lowered when Cu replaces Fe. The effects of Fe substitution by Cu on the saturation magnetization and the anisotropy field are presented.

The nucleophilic substitution of hydrogen to synthesize the sulphonyl indazole derivatives 9-16 is described. The structures of the substitution products are discussed using H-NMR spectra. Chemical structural proof was given by steric hindrance observed in the process of chorination of 9-16. The compounds 3, 4, 7, 8, 14, and 16 are studied to find an inhibition on phospholipase-A2 and lipoxygenase-I.