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

Using neutron diffraction the magnetic form factor f of oxygen is investigated in the solid monoclinic cr-phase (2' < 23.88 OK). The antiferromagnetic reflections of cr-0, (001) and (loo), containing the purely spin magnetic scattering on x-electrons, may give the values of f for sin 012 equaling to 0.1047 and 0.1242, respectively. The data of magnetic diffraction on KO, are also considered: in the magnetic structure proposed the antiferromagnetic reflections (001) and (110) (sin O/A is equal to 0.0735 and 0.1260, respectively) are again due to the orientation of the Tc-orbital spin moments (orbital moment is frozen). The whole set of obtained values f for 0, and 0; are in reasonable agreement with the calculated dependences of f. MeTOHOM HII@paKUMkI HeiTPOHOB IICCJIeHyeTCR MarHLlTHbIn @OPM-#aKTOP KIICJIO-pOAa f B TBepHOn MOHOKJIHHHOfi Ct-@a3e (T < 23,88 O H ) . AHTH@ePPOMarHHTHbIe oTpameHm cr-0, (001) EI (loo), conepmawie WCTO cnmoBoe MarHmHoe pacceHm e Ha x -m e~~p o~a x IIO~BOJIIIJIH I I~B J I~Y~ 3~a q e~m f UJIH sin O/A, pamoro 0,1047 M 0,1242, COOTBeTCTBeHHO. TaK me PaCCMOTpeHM HaHHble MarklMTHOfi AH@paKUHU Ha KO, : B npe&llOHteHHOfi MaI' HATHOft CTPYKTYpe aHTPi@eppOMarHHTHbIe OTpa-HCetIIIR (001) II (110) (Sin e p paBeH 0,0735 M 0,1260, COOTBeTCTBeHHO) BHOBb o6ycno-BJIeHbI OpEIeHTaUMefi CnMHOBbIX MOMeHTOB (Op6MTaJIbHbIfi MOMeHT 3aMOpOMeH) x -o p 6~~a n e t .COBOKYnHOCTb IlOJIyqeHHbIX 3HaseHMfi f nJIH 0, M 0, YAOBJIeTBOPH-TeJIbHO COrJIaCyIOTCH C BbIWXCJIeHHbIMH 3aBMCHMOCTRMH &TIII f .

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