Study of exchance bias field variation in ferrimagneticiferrimagnetic bilayer system

During the last ten years, a lot of work have ken devoted to the understanding of the magnetisatiun reversal processes involve in exchange coupled bilayers. In such system B shift of the hysteresis loop (toward an exchange bias field HE) may be observed fur a temperature lower than a blocking temperature Tb. We present the study of an amorphous bilayer GdmFeul(lOOnm) ,TbliFegx(50nm) lor which both positive and negative exchange bias is observed depending on the cooling field procedure. A uni-dimensional micro-magnetic model permils to reproduce the various measured hysteresis loop and give a full understanding 01 the magnclimlion reversal proccsscs involvcd.