Magnetic resonant x-ray diffraction study of europium telluride

Abstract

Here we use magnetic resonant x-ray diffraction to study the magnetic order in a 1.5 m EuTe film grown on ͑111͒ BaF 2 by molecular-beam epitaxy. At Eu L II and L III absorption edges, a resonant enhancement of more than two orders was observed for the → Ј diffracted intensity at half-order reciprocal-lattice points, consistent with the magnetic character of the scattering. We studied the evolution of the ͑ 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 = 9.99͑1͒ K and a critical exponent ␤ = 0.36͑1͒, 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 ͑

Theory of near-gap second harmonic generation in centrosymmetric magnetic semiconductors: Europium chalcogenides

“…However, our target was to compare the theory with experiments performed on EuTe thick layer samples ͑about 1 m thickness͒ grown by molecular-beam epitaxy ͑MBE͒, and therefore only a single T domain parallel to the ͑111͒ substrate was included in the calculations, because the other domains of equivalent energy present in isotropic samples are suppressed in MBE samples due to residual strains. 25 Within the existing T domain, all three S domains are found experimentally to be present in samples grown by MBE, 26 thus three S domains were included in the calculations.…”

Luminescence properties of magnetic polarons in EuTe: Theoretical description and experiments in magnetic fields up to 28 T

“…The samples were grown by molecular beam epitaxy on BaF 2 substrates [36]. The thickness of the epitaxial layers was in the range 1-4.2 μm.…”

Optical second harmonic generation in the centrosymmetric magnetic semiconductors EuTe and EuSe

“…State of the art for EuX technology is that MBE grown epilayers have much higher structural and optical quality compared to bulk single crystals. 59,88 For higher order nonlinear optical effects the sample quality is a very important and often decisive factor. Requirements such as chemical stoichiometry and sample stability, structural and optical homogeneity, absence of impurities, partial SHG phase matching are easier fulfilled in MBE epilayers than in bulk crystals of EuX.…”