MAGNETIC-PROPERTIES OF FE-57 IR(100) SUPERLATTICES/

The synthesis of a new BCT Fe phase was performed in Fe/Ir(100) superl attices grown by MBE. Magnetic propel ties of Fe-57/Ir(100) super latt ices with 4 ml Fe and variable Ir thickness (2-30 Angstrom) are invest igated by Fe-57 conversion electron Mossbauer spectroscopy in the 4.2- 300 K temperature range. Two spectral components are evidenced, relate d, respectively, to Fe atoms involved in the central part of the iron layers and at the interface between iron and iridium layers. The appea rance of a high magnetic hyperfine splitting in the iron BCT structure above a volume threshold of 12 Angstrom(3) is evidenced. Marked diffe rences are observed between the mean magnetic properties and the local ones suggesting strong relaxation effects.