Application of the Inverted-Neutron-Filter Technique to the Study of Inelastic Scattering by Paramagnetic Substances
1966; American Institute of Physics; Volume: 147; Issue: 2 Linguagem: Inglês
10.1103/physrev.147.457
ISSN1536-6065
Autores Tópico(s)Nuclear Physics and Applications
ResumoUsing the filter-cutoff method we have measured the quasielastic scattering of slow neutrons from several paramagnetic compounds. Our results for Mn${\mathrm{F}}_{2}$ at large scattering angles are in reasonable agreement with time-of-flight measurements by Cribier and Jacrot. For small scattering angles we have confirmed the Lorentz-like form of the energy distribution of scattered neutrons predicted by de Gennes. Similar measurements at large and small scattering angles on a partially inverted sample of Mn${\mathrm{Al}}_{2}$${\mathrm{O}}_{4}$ did not exhibit the predicted angular dependence. This suggests that the assumption of $A\ensuremath{-}A$ interactions only is inappropriate for this compound. From the temperature dependence of the intensity of the (200) magnetic reflection, a N\'eel temperature of 18\ifmmode^\circ\else\textdegree\fi{}K was deduced for the Mn${\mathrm{Al}}_{2}$${\mathrm{O}}_{4}$. Our results demonstrate that with an adequate flux of long-wavelength neutrons the inverted-filter technique can be employed successfully in studies of paramagnetic scattering.
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