A. WANIC (a), and W. WOLSKI (d) Neutron spectrometric investigations are made of goethite (a-FeOOH) of mineralogical and synthetic origin (a-FeOOH of natural isotopic composition) and also of a-FeOOD using a monochromatic neutron beam of I = 1.12 A. Some powder diffraction patterns in the temperature range from -190 to +120 "C are measured. The obtained coordinates for all atoms (including those for hydrogen) in the unit cell are given. The existence of antiferromagnetic spin ordering a t temperatures below +SO "C is observed. A model is proposed in which the spins are aligned parallel to the b-axis. EbIn EICCJIeHOBaH reTIIT (cc-FeOOH) MuHepanora4ecKoro IIPOMCXOmAeHHR EI CEIH-TeTElseCHIlfi (eCTeCTBeHHOr0 E130TOnWleCKOrO COCTaBa) a TaKme AefiTepEI3OBaHHbIfi W T H T a-FeOOD. kICCJIeAOBaHHfI BeJIEICb B B m s a (~rOCJIaBEIH) IIpH peaKTope PA. ,&JIH M3MepeHHn HCIZOJI3OBPHO KPaKOBCKllfi HefiTpOHHblfi KpEICTNIJlEI~eCKEl~ CIIeK-TpOMeTp EI IIyuOK HefiTpOHOB C AJIUHOfi BOJlHbI A = 1,12 A. TeMnepaTypa o6paaua U3MeHIIJIaCb B IIpeAeJlaX OT -190 HO +I20 "c. YTOYHeHO HOOPAEIHaTbI aTOMOB BbInO 06HapymeHO CyrrleCTBOBaHIIe aHTEl-meneaa II wicnopona B s n e~e~~a p~o t m e h e , a TaKme B nepwfi pa3 6b1no onpe-#eppoMarHmHoro ynopHAoseHm CIIEIHOB EIOHOB meneaa B TeMnepaTypax HHme +80 "C. ~P M B O A E I T C R MoAen C~E~H O B O~~ peluema B KOTOPOP C~E I H~I napanenmb1 OCM b.HeJIeHO IIOJIOmeHEIe aTOMOB BOAOpOAa.

No abstract

Saturation magnetization, X‐ray and neutron diffraction measurements were made on ferromagnetic alloys in the compositions Ni2MnSb, Ni2MnSn, and Co2MnSn. The compounds investigated have a crystallo‐chemical structure of L21 type, with a partial disorder among NiSb atoms in the case of Ni2MnSb and Ni(Co)‒Mn atoms in that of Ni2MnSn and Co2MnSn. It was also found that in Heusler alloys the Ni atoms have zero magnetic moment, but the Co atom has a magnetic moment different from zero. The values of the magnetic moment of Mn and Co atoms were also calculated at 80 °K and found to be μMn = 3.60 to 3.75 μB, μCo = 0.7 μB.

MeasurementsThe measurements were done a t Vinca, using the Cracow neutron spectrometer [9]. The magnetic inelastic scattering of a monoenergetic (A = 1.124 A) unpolarized neutron beam was investigated. A single crystal of Cr,03 was kept in a cryostat at liquid nitrogen temperature. The sample was a 8 mm thick skew slice split from a rod-like ingot 10 mm in diameter. It had its flat elliptic surface parallel to the (011) set of planes. The crystal could be rotated inside the cryostat around the (01 1) reciprocal lattice vector aligned horizontally, and it could be turned around the vertical axis together with the cryostat mounted on the spectrometer table. The cone of magnon scattering connected with z = (011) was observed and scanned by a detector system supplied with a collimator of definite aperture K . Various horizontal Kil and vertical K , apertures were used. The shapes of the magnon reflections were found and the slopes located for a number of missetting angles A0 (see Figs. 1 and 2) essentially in the way described elsewhere [7, 81. However, here it was assumed that for any reflection (irrespective of its shape) the position of the edge (PI or Pr) of the scattered cone is given by the point in the middle of the slope (see Fig. 2). For larger Ae-angles the reflections were so wide that the collimator could not perform a one-dimensional integration of their intensity. For this reason they

Neutron depolarization studies using pulsed polarized neutrons have been performed to get information on mean magnetization, static magnetization fluctuations and magnetic anisotropy in plate-like ferromagnetic samples. The approach to magnetic saturation of polycrystalline ferromagnets ((Fe50Ni50)96Cr4, and MnZn-ferrit) was studied by analysing the field dependence of depolarization parameters