Order and magnetic properties of Fe 89− xMn 11Al x alloys: magnetization measurements and X-ray diffraction

Abstract

We report experiments performed on a series of fourteen Fe 89− x Mn 11Al x alloys in the concentration range 2 at.%<x<40 at.% examining structure, degree of long range order and the magnetic properties. We found the type of long range order is concentration dependent, changing from A2, crossing a DO 3 region up to B2. The structural order found in this system is of great influence on the magnetic moments of the Fe atoms. Therefore the wide concentration range of the alloys investigated allowed us to observe the change from ferromagnetism via a region of re-entrance from ferromagnetism to spin glass till antiferromagnetism. In the re-entrant concentration range, we derive the magnetic field dependence on characteristic temperatures for the alloys Fe 62Mn 11Al 27 and Fe 59Mn 11Al 30 and demonstrate that the latter is very near the critical concentration where the Curie temperature and the freezing temperature of the re-entrant spin glass become equal.