Element-Specific Magnetic Anisotropy Determined by Transverse Magnetic Circular X-ray Dichroism

Abstract

Understanding of the magnetocrystalline anisotropy in magnetic materials (the influence of different elemental components on the direction of easy magnetization) can be greatly enhanced by measuring the orbital moment anisotropy of the elemental constituents. A circular x-ray dichroism technique is presented that allows the determination of the microscopic origin of the spin reorientation transition in ultrathin single-crystalline cobalt/nickel films. The stronger anisotropy contribution of a much thinner cobalt layer redirects the easy magnetization direction of the entire film.

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

“…In Fe, Co, Ni, and their alloys, the 3d band is over half-filled; the spin-orbit coupling should restrict the maximal component of the orbital moment vector m l to be parallel to the spin moment vector m s (and hence magnetization). However, the crystal field interaction causes the orbital magnetic moment vector to be confined to a given high-symmetry direction 25 depending, in a non-trivial fashion, on factors such as the lattice spacing, orbital population etc. 26 .…”

“…For both films the ratio of orbital to spin magnetic moments are extracted using sum-rule analysis 105 , and are found to be m l /m s = 0.21 for Co, and m l /m s = 0.11 for Fe (not shown), apparently independent of the underlying semiconductor material. For a ferromagnet with only uniaxial anisotropy, m l /m s measured along the uniaxial easy axis should be proportional to the degree of anisotropy in m l , and hence to the effective uniaxial magnetic anisotropy 25,27 . However, in this case there is also a volume cubic magnetocrystalline anisotropy with similar strength to the interface induced uniaxial magnetic anisotropy: the measured anisotropy in m l is due predominantly to the magnetocrystalline anisotropy, owing to the short penetration-depth of electron-yield XMCD.…”

Magnetic structure of La0.7Sr0.3MnO3/La0.7Sr0.3FeO3 superlattices

“…For instance, epitaxial strain induces a perpendicular magnetic anisotropy in Ni thin films grown on Cu(001) [1] but deposition of three monolayers of Co with a preferential in-plane orientation of the moments forces the Ni moments into the surface plane [2] due to the strong exchange interaction through the Co/Ni interface. Another example is cooling a ferromagnetic (FM)/ antiferromagnetic (AFM) bilayer in an external magnetic field through the Néel temperature of the antiferromagnet causing a shift in the FM hysteresis loop away from zero field.…”

Anisotropic spin-density distribution and magnetic anisotropy of strained La1−xSr x MnO3 thin films: angle-dependent x-ray magnetic circular dichroism

“…Especially, in the geometry where M spin is perpendicular to the incident x-rays [so-called transverse XMCD (TXMCD) geometry], 11 one can extract the pure M T component. Although TXMCD has been theoretically studied since two decades ago, [10][11][12][13][14] there have been only few experimental reports [15][16][17][18] because the direction of the magnetic field is fixed parallel or nearly parallel to the incident x-rays in conventional XMCD measurement systems. Recently, we have developed an apparatus for angle-dependent XMCD experiments using a vectortype magnet where the direction of the magnetic field can be rotated using two pairs of superconducting magnets.…”