Catálogo de publicaciones - revistas

<jats:p> The magnetic properties and magnetoresistance effect of YMn<jats:sub>6</jats:sub>Sn<jats:sub>6-<jats:italic>x</jats:italic> </jats:sub>Cr<jats:sub> <jats:italic>x</jats:italic> </jats:sub> (<jats:italic>x</jats:italic> = 0-0.8) compounds have been experimentally studied by magnetic properties and resistivity measurements in the applied field range 0-5 T. The compound (<jats:italic>x</jats:italic> = 0.8) displays a ferromagnetic behaviour, while the compounds (<jats:italic>x</jats:italic> = 0-0.4) display an antiferromagnetic behaviour in the whole ordering temperature range. The compounds (<jats:italic>x</jats:italic> = 0.5, 0.6) experienced a transition from an antiferromagnetic state to a ferromagnetic state with increasing temperature. The compound with <jats:italic>x</jats:italic> = 0.8 is rapidly saturated in the lower magnetic field with saturation magnetization of 35.92 emu/g. The compounds (<jats:italic>x</jats:italic> = 0-0.6) display a field-induced metamagnetic transition, and the threshold fields decrease with increasing Cr content. The cell-volume <jats:italic>V</jats:italic> of compounds (<jats:italic>x</jats:italic> = 0-0.8) increases, and the ordering temperature decreases with the increasing Cr content. A large magnetoresistance effect was observed for the compounds (<jats:italic>x</jats:italic> = 0.4, 0.5), and the maximum absolute value at 5 K are 32% and 24% under 5 T for <jats:italic>x</jats:italic> = 0.4 and <jats:italic>x</jats:italic> = 0.5, respectively.</jats:p>

<jats:p> Numerical modelling of velocity and temperature fields in high-temperature KNbO<jats:sub>3</jats:sub> melt of a loop-shaped Pt wire heater is carried out by using the commercial computational code ANSYS for the mathematical solution of the governing equations. Based on the experimental boundary conditions and the Boussinesq approximation, the numerical modelling of a steady and two-dimensional model is applied to study the process under consideration of the buoyancy-driven convection condition. The result is compared with the previous experimental and theoretical data obtained in our laboratory, and the former is in agreement with the latter. Thus a theoretical guide for reasonable growth conditions is provided by studying in depth the real fluid flow effects in the crystal growth from the melt.</jats:p>