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 antiferromagnetic (AF) phase with a propagation vector k = 1/2 1/2 1/2 transforms into another AF one with k = 1/4 1/4 1/4, then into a ferromagnetic phase. The observed sequence of magnetic transitions qualitatively confirms the proposed models of competing ferromagnetic and antiferromagnetic interactions in the EuX family (X = O, S, Se, Te). Nevertheless, a quantitative analysis of our data shows some differences with microscopic models. The structural transition from NaCl to CsCl phase occurs between 13 and 17 GPa. Interestingly, we do not observe any long-range magnetic order in the high-pressure CsCl phase.