MAGNETIC ORDER IN EUTE UNDER PRESSURES UP TO 17GPA - A NEUTRON STUDY

We studied magnetic order in EuTe by neutron diffraction under applied pressures up to 17 GPa. In the range P < 11GPa, the original antiferr omagnetic (AF) phase with a propagation vector k = 1/2 1/2 1/2 transfo rms into another AF one with k = 1/4 1/4 1/4, then into a ferromagneti c phase. The observed sequence of magnetic transitions qualitatively c onfirms the proposed models of competing ferromagnetic and antiferroma gnetic interactions in the EuX family (X = O, S, Se, Te). Nevertheless , a quantitative analysis of our data shows some differences with micr oscopic models. The structural transition from NaCl to CsCl phase occu rs between 13 and 17 GPa. Interestingly, we do not observe any long-ra nge magnetic order in the high-pressure CsCl phase.