Structural and magnetic properties of a chemically ordered face-centered-cubic (111) Mn alloy film

A 4 ML Ni∕W(110) substrate is used to establish a (111) face-centered-cubic (fcc) template upon which 3 ML of Fe is deposited and annealed to 580K to form a substrate with very good short and long range fcc (111) order, that is Fe rich at the surface. Mn alloy films are formed by annealing a subsequent Mn deposit of 0.3–1.6 ML. Low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and directional AES show that an ordered alloy is not formed until an annealing temperature of 580K, upon which a multilayer alloy with a P(23×23)R30° LEED pattern is created. The alloy films formed from 0.3 to 0.5 ML of Mn have magnetic properties similar to the FeNi substrate. Hysteresis loops and ac-susceptibility curves measured using the Kerr effect give square loops with a ferromagnetic moment along the in-plane fcc [-211] direction and a Curie temperature TC of about 460K. There is an increase in coercive field likely due to the inhomogeneities introduced by the Mn. Alloy films formed from 0.8 to 1.6 ...