Estudio de propiedades estructurales y magn?ticas de aleaciones de tierras raras y metales de transici?n

101 p. Recurso Electr?nicoEn el presente trabajo se reporta el estudio de las propiedades estructurales y magn?ticas de polvos de Gd0.257-xTbxFe0.743 con x = 0, 0.1285, y 0.257, preparadas por Aleamiento Mec?nico (MA) en atm?sfera de arg?n durante 48 y 72 horas mediante un molino planetario de alta energ?a. La caracterizaci?n estructural se realiz? por medio de Difractometr?a de rayos X (XRD), para la caracterizaci?n magn?tica se utiliz? la espectroscopia M?ssbauer y ciclos de hist?resis de las muestras utilizando un magnet?metro de muestra vibrante VSM (Vibration Sample Magnetometry) de un sistema PPMS (Physical Property Measurement System). La fase ?-Fe se presenta, en difracci?n de rayos-x, para todo x, mediante un pico caracter?stico cuya intensidad permanece ligeramente constante; sin embargo un aumento de su ancho al sustituir el Gd por el Tb se observa, que se correlaciona con una disminuci?n del tama?o de cristalito de la fase ?-Fe. Los resultados de los espectros M?ssbauer a temperatura ambiente indican que el sistema presenta un comportamiento ferromagn?tico para todas las composiciones y los ciclos de hist?resis revelan que presenta un comportamiento magn?ticamente semiduro, que es una propiedad importante de materias prima para memorias magneto-?pticas. Palabras Clave: Aleamiento mec?nico, Difractometr?a de rayos X, Espectroscopia M?ssbauer, Sistema GdTbFe.In present work the study of the structural and magnetic properties of powders of composition Gd0.257-xTbxFe0.743 with x = 0, 0.1285, 0.257, prepared by Mechanical Alloying (MA) in argon atmosphere, during 48 and 72 hours, using a high energy planetary ball mill is reported. The structural characterization was performed by means of X-ray diffractometry (XRD); and for the magnetic characterization M?ssbauer spectroscopy was used, the hysteresis cycles of the samples were obtained using the VSM (vibration sample magnetometry) of a PPMS (Physical Property Measurement System). The ?-Fe phase is presented, in the RDX patterns, for all x, by a characteristic peak whose intensity remains slightly constant, however, an increase of its width is obtained when the Gd is replaced by the Tb, which is associated to a decrease in the crystallite size of the ?-Fe phase. The M?ssbauer results at room temperature indicate that the system exhibits a ferromagnetic behavior for all compositions, and the hysteresis cycles show that it exhibits a magnetically semi-hard behavior, which is an important characteristic for raw material for magneto-optical memory. Keywords: Mechanical alloying, X-ray diffraction, M?ssbauer spectroscopy, GdTbFe System