DFT insights into the origin of d0 ferromagnetism, mechanical stability, elastic, and acoustic anisotropy in AZrO3 (A= K, rb, Cs) cubic perovskites

Abstract

The d0 ferromagnetism through hole induction can be realized in oxide perovskites. The electronic and magnetic properties of AZrO3 (A = K, Rb, and Cs) cubic perovskites have been computationally analyzed using generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) potentials. From the evaluation of tolerance factor, volume optimization, formation energy, and phonon dispersion, their structural, magnetic, and dynamical stabilities in the ferromagnetic cubic phase have been verified. Additionally, Blackman's and Every's diagrams ensure their elastic stability without any symmetry-breaking phase transitions. The three-dimensional surfaces of elastic moduli and acoustic wave velocities indicate the degree of anisotropy in these perovskites. The compounds become more ductile for larger alkali cations. The band structures from both functionals confirm that the localized magnetic moments around oxygen atoms arise only from the exchange spin splitting of O-2p orbitals. The integer magnetic moment of 1 μB and complete spin polarization implies the presence of half-metallic ferromagnetism. Among the proposed compounds, the predicted mean-field curie temperature of CsZrO3 is above room temperature and may serve as optimal magnetic layers in spin-valve sensors and magnetic tunnel junctions.