The origin of the magnetic anisotropy is explained in an assembly of aligned magnetic nanoparticles. For that, nanoparticles synthesized biologically by Magnetospirillum magneticum AMB-1 magnetotactic bacteria are used. For the first time, it is possible to differentiate between the two contributions arising from the alignment of the magnetosome easy axes and the strength of the magnetosome dip...

Off-axis electron holography in the transmission electron microscope was used to correlate the physical and magnetic microstructure of magnetite nanocrystals in magnetotactic bacteria. The magnetite crystals were all single magnetic domains, and the magnetization directions of small superparamagnetic crystals were constrained by magnetic interactions with larger crystals in the chains. Shape an...

We propose a new mechanism for surface-induced magnetic anisotropy to explain the thickness dependence of the Kondo resistivity of thin films of dilute magnetic alloys. The surface anisotropy energy, generated by spin-orbit coupling on the magnetic impurity itself, is an oscillating function of the distance d from the surface and decays as 1/d2. Numerical estimates based on simple models sugges...

The temperature dependence of the effective magnetic anisotropy constant, K(T), of MnFe2O4 nanoparticles is obtained based on superconducting quantum interference device magnetometry measurements. The variation of the blocking temperature, TB, as a function of particle radius, r, is first determined by associating the particle size distribution and the anisotropy energy barrier distribution ded...

We use a method which combines the discretized path-integral representation (DPIR) with the double-chain approximation (DCA) to study the thermodynamic properties of an S ˆ 1 antiferromagnetic Heisenberg chain (AFHC) with both uniaxial and non-uniaxial single-ion anisotropy. The magnetization in the presence of an external magnetic field, the zero-field magnetic susceptibility and the magnetic ...

It is challenging to determine domain wall pinning energy and magnetic anisotropy since both coherent rotation and domain wall displacement coexist during magnetization switching process. Here, angular dependence anisotropic magnetoresistance (AMR) measurements at different magnetic fields were employed to determine magnetic anisotropy constants and domain wall pinning energy of Fe/MgO(001) ult...

In this paper we experimentally studied GMI effect and soft magnetic behavior of Co-rich microwires. Correlation between magnetoelastic anisotropy and magnetic field dependences of diagonal and off-diagonal impedance components are observed. Low field GMI hysteresis, explained in terms of magnetoelastic anisotropy of microwires, has been suppressed by the bias current.

Strong size-dependent variations of the magnetic anisotropy of embedded cobalt clusters are evidenced quantitatively by combining magnetic experiments and advanced data treatment. The obtained values are discussed in the frame of two theoretical models that demonstrate the decisive role of the shape in larger nanoparticles and the predominant role of the surface anisotropy in clusters below 3 n...