Epitaxial growth and interface roughness of PdMn/Fe bilayer structures grown by ion-beam sputtering

摘要

Different orientations of PdMn films and different stacking orders of PdMn and Fe on MgO(001) were studied. At low temperatures (T< 280℃) dominated by the kinetics of growth, α-axis orientated [PdMn(100)/Fe(001)/MgO(001)] was stabilized whilst c-axis [PdMn(001)/Fe(001)/MgO(001)] were obtained at higher temperatures (T> 300℃). The inverted structures, Fe(001)/PdMn(001)/MgO(001) and Fe(001)/PdMn(100)/MgO(001), were obtained epitaxially for the first time. The magnetic exchange coupling (H_e) of these PdMn/Fe bilayers show a wide range in values: ～10 Oe for annealed a-axis samples, ～33 Oe for c-axis normal samples and ～68 Oe for c-axis inverted samples. The interface roughness of these samples was characterized by energy-filtered transmission electron microscopy (EFTEM). The orientation relationships were confirmed by x-ray diffraction and TEM. The possible origins for the H_e difference in a-axis and c-axis growth samples and the normal and inverted samples are discussed.