%0 Journal Article
%4 dpi.inpe.br/plutao@80/2008/12.04.13.32
%2 dpi.inpe.br/plutao@80/2008/12.04.13.32.10
%@doi 10.1103/PhysRevB.78.134423
%@issn 1098-0121
%F lattes: 0875527722518904 3 DíazGrAbRaChHe:2008:MaReXr
%T Magnetic resonant x-ray diffraction study of europium telluride
%D 2008
%9 journal article
%A Díaz, B.,
%A Granado, E.,
%A Abramof, Eduardo,
%A Rappl, Paulo Henrique de Oliveira,
%A Chitta, V. A.,
%A Henriques, A. B.,
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto de Física “Gleb Wataghin”, UNICAMP
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto de Física, Universidade de São Paulo
%@affiliation Instituto de Física, Universidade de São Paulo
%@electronicmailaddress bdiazmoreno@gmail.com
%@electronicmailaddress
%@electronicmailaddress abramof@las.inpe.br
%@electronicmailaddress rappl@las.inpe.br
%B Physical Review B
%V 78
%N 134423
%P 1-6
%K difração magnética de raios x ressonante, ordenamento magnético, telureto de európio.
%X Here we use magnetic resonant x-ray diffraction to study the magnetic order in a 1.5 m EuTe film grown on (111) BaF_2 by molecular-beam epitaxy. At Eu LII and LIII absorption edges, a resonant enhancement of more than two orders was observed for the sigma →pi' diffracted intensity at half-order reciprocal-lattice points, consistent with the magnetic character of the scattering. We studied the evolution of the (1/2 1/2 1/2) magnetic reflection with temperature. When heating toward the Neel temperature (T_N), the integrated intensity decreased monotonously and showed no hysteresis upon cooling again, indicating a second-order phase transition. A power-law fit to the magnetization versus temperature curve yielded T_N=9.99(1) K and a critical exponent beta=0.36(1), which agrees with the renormalization theory results for three-dimensional Heisenberg magnets. The fits to the sublattice magnetization dependence with temperature, disregarding and considering fourth-order exchange interactions, evidenced the importance of the latter for a correct description of magnetism in EuTe. A value of 0.009 was found for the (2j_1+ j_2)/J_2 ratio between the Heisenberg J_2 and fourth-order j_1,2 exchange constants. The magnetization curve exhibited a round-shaped region just near T_N accompanied by an increase in the magnetic peak width, which was attributed to critical scattering above T_N. The comparison of the intensity ratio between the (1/2 1/2 1/2) and the (1 1/2 1 1/2 1 1/2) magnetic reflections proved that the Eu^2+ spins align within the (111) planes, and the azimuthal dependence of the (1/2 1/2 1/2) magnetic peak is consistent with the model of equally populated S domains.
%@language en
%3 PhysRevB.78.134423.pdf