Magnetic properties of ball-milled Fe-Mn alloys

S. M. COTES; A. F. CABRERA; L. DAMONTE; R. MERCADER; J. DESIMONI

Centro Atomico Bariloche, San Carlos de Bariloche, Río Negro, Argentina

Workshop; Latin American Workshop on Magnetism and Magnetic Materials and their Applications (LAW3M); 2001

LAW3M

Para-antiferromagnetic transformations in hcp ball-milling Fe-M <!-- @page { size: 21.59cm 27.94cm; margin: 2cm } P { margin-bottom: 0.21cm } --> The hcp phase in the Fe-Mn system is metastable and its magnetic properties are poorly known. It can be obtained by certain thermo and/or mechanical treatments only for compositions greater than 13 wt % Mn. In this work we explore the possibility to obtain hcp phase in the low composition range (<13 wt % Mn) by ball milling. The alloys of adequate composition were previously prepared by arc melting from pure elements, quenched from 1273K and then subjected to ball milling for various times. The composition of the alloys was stablished by WDS microprobe.The evolution of the induced structural transformations was characterized by Mossbauer spectroscopy, X-ray difraction, calorimetry and AC susceptibility. Mossbauer spectroscopy and X-ray difraction on quenched and milled samples reveal the presence of bcc and hcp phases. The amount of hcp phase, which can be evaluated from Mossbauer spectra, varies with milling times. Preliminar AC susceptibility meassurements show, in spite of the ferromagnetic behaviour of the bcc phase, the paramagnetic/antiferromagnetic transformation of the hcp phase.