Magnetic anisotropy and coercivity in MgO/Fe (tFe)/Ag films

Magnetic systems with reduced dimensionality show critical features, such as perpendicular surface anisotropy, enhanced magnetic moment. We have compared the magnetic properties of the iron thin films deposited by electron beam evaporation onto MgO and glass/Ag(buffer) substrates. The steps on the MgO(001) substrates of height =4.1 nm were imagined by AFM. FMR has been employed to study the magnetic anisotropy HK, and coercivity HC was measured using VSM. In the iron films on MgO substrate the strong in-plane fourfold anisotropy (K1=4.8x104 J/m3 for tFe=23nm) was observed. The anisotropy field scales with the iron film thickness. HC appeared to be significantly reduced in comparison with HK (HK=2K1/M=10xHC). This result was ascribed to the pinning effects occurring at the steps on the substrate surface. The iron films on glass/Ag were characterized by weak uniaxial anisotropy (Ku=0.28x104 J/m3) consistent with the coercivity

Neutron diffraction and X-ray photoemission studies of the RNi4Cu compounds (R=Ce, Pr, Nd)

The RNi sub 4 Cu compounds for R Ce, Pr and Nd have been studied both by neutron diffraction and X ray photoemission spectroscopy XPS . The valence band region shows the dominance of the Ni 3d and Cu 3d states. The higher degree of the f states localization for NdNi sub 4 Cu implies a magnetically ordered ground state, which has made possible the observation of magnetic contribution in the neutron diffraction experiment. CeNi sub 4 Cu is characterized by an anomaly at 6 K in the specific heat but it does not exhibit any additional reflections in the neutron diffraction pattern at 4 K, which should be visible in the case of antiferromagnetis

Crystal field manifestation in inelastic neutron scattering, magnetic susceptibility and specific heat of the antiferromagnetic CeCoAl4

Inelastic and quasielastic excitations in the neutron scattering on the compounds CeCo1 xCuxAl4 x 0, 0.05, 0.1 have been studied above and below the antiferromagnetic ordering temperature. The quasielastic contribution disappears below the Neel temperature, T N 13.5 K, and its linewidth Gamma 2 is below T N, therefore these results suggest that Kondo screening is not relevant in these Ce compounds. Based on the example of CeCoAl4 we show that the inelastic excitations provide crystal electric field energy levels scheme, which in consistent way describes both the magnetic susceptibility and the specific heat. The inelastic neutron scattering spectrum below T N is interpreted as the splitting of the crystal electric field levels by the internal molecular fiel