%0 journal article
%@ 0021-3640
%A Grigoriev, S.V.,Okorokov, A.I.,Chetverikov, Y.O.,Chernyshev, D.Y.,Eckerlebe, H.,Pranzas, P.K.,Schreyer, A.

%D 2006
%J JETP Letters
%N 11
%P 478-482 
%R doi:10.1134/S0021364006110026
%T Investigation of the chiral structure of the Y/Dy multilayer system by the method of the small-angle scattering of polarized neutrons
%U https://doi.org/10.1134/S0021364006110026
11 
%X The magnetic spiral structure of a Y/Dy sample has been investigated for temperatures from 30 to 190 K by the method of the small-angle scattering of polarized neutrons. The sample is a sequence of layers Y50nm  [Dy4.3nm  /Y2.8nm  ]350/Y234nm  /Nd200nm  Al2O3 (substrate) that is grown as a single crystal with the [001] axis of the hexagonal lattice, which is perpendicular to the layer plane. The experiments demonstrate the appearance of the magnetic peak below T  N = 165.4 K, which is associated with the helicoidal phase, and the helicoid coherence length is larger than the layer thickness of the Y/Dy layer. The use of polarized neutrons allows the separation of the polarization-independent and polarization-independent components of magnetic scattering. The polarization-independent component of the magnetic neutron cross section is proportional to magnetization squared 〈S   Z  〉2, whereas the polarization-dependent component is proportional to the average chirality of the system 〈C〉 = 〈[·S  1 × S  2]〉. The critical exponents βC = 1.02(1) and β = 0.39(1) have been determined for the average chirality and magnetization, respectively. The magnetization critical exponent β for Dy/Y coincides with the exponent obtained for Dy bulk samples. The difference βC − 2β = 0.24(2) shows that the chirality can be a component of the order parameter that is independent of magnetization.