Epitaxial growth, structure, and magnetism of epitaxial Ni₈₀Fe₂₀ single-crystal, bicrystal, and quad-crystal films

The structure and magnetism of epitaxial Ni₈₀Fe₂₀ films grown on stepped and nonstepped Mo(001) planes and MgO(110) substrate have been studied. Single-crystal Ni₈₀Fe₂₀(110) films were prepared on MgO(110) substrates. Bi-crystal Ni₈₀Fe₂₀(110) films were stabilized on Mo(001) nonstepped planes. On Mo(001) stepped surfaces, interestingly enough, quad-crystal Ni₈₀Fe₂₀(110) films with rough surfaces were formed above ∼200°C and single-crystal Ni₈₀Fe₂₀(001) films with smooth surfaces were formed below ∼100°C. Thick films (>300 Å) of single-crystal, bicrystal, and quad-crystal Ni₈₀Fe₂₀(110) show uniaxial, biaxial and isotropic magnetic behavior, respectively. The easy axis of the single-crystal Ni₈₀Fe₂₀(001) is directed along the Mo step edge direction and the M-H loop along the hard axis reveals a two-step magnetic moment rotation process. The magnetic anisotropies of the Ni₈₀Fe₂₀ films were determined by vibrating sample magnetometer. Details of the epitaxial growth and interplay of structure and magnetism of these Ni₈₀Fe₂₀ films are presented.