A comparative study of cubic Heusler alloys Ni₂MnX (X = Al, Ga, In) was performed to explain the differences in material properties using a first-principles electronic structure calculation of quasi-particle self-consistent GW (QSGW) method. The obtained electronic structures indicate a similar density of states (DOS) of Ni 3d e_g orbitals on the Fermi level for all the studied materials, implying a promotion to a band Jahn-Teller (BJT) distortion. The generalized susceptibility analysis suggests some instability of the cubic high symmetry phase and indicates, that the Ga containing material is the one which is the most pronounced to 10M modulation due to this instability. Taking the advantage of accurate first-principles electronic structure calculations performed by QSGW, the U parameters of Hubbard correction on Mn and Ni atoms were determined using the density functional theory (DFT) approach with generalized gradient approximation (GGA), so that the local and total QSGW magnetic moments are reproduced.

  We investigated the magnetic anisotropy of NiCo₂O₄ thin film with a relatively large second-order magnetic anisotropy, which gives rise to easy-cone magnetic anisotropy. Anomalous Hall data measured in external magnetic fields at various angles were analyzed based on the generalized Sucksmith-Thompson (GST) method to quantitatively extract both the first- and second-order anisotropy constants. Although the GST model is valid for any external field angle, we found that the analysis was useful only when the field was either parallel or normal to the film plane. However, the tilted magnetic field results show the effect of misalignment between the actual and expected angles of the field. Our results indicate the validity of estimating higher-order magnetic anisotropy and adjusting the misalignment of measurement systems.