Temperature dependence of magnetic anisotropy constant in iron chalcogenide Fe3Se4: Excellent agreement with theories

Abstract

Magnetic hysteresis loops were measured for ferrimagnetic iron chalcogenide Fe 3 Se 4 nanoparticles in the whole temperature range below the Curie temperature T C (315 K). The coercivity of the material is huge, reaching about 40 kOe at 10 K. The magnetic anisotropy constant K was determined from the magnetic hysteresis loop using the law of approach to saturation. The deduced anisotropy constant at 10 K is 5:22 Â 10 6 erg=cm 3 , which is over one order of magnitude larger than that of Fe 3 O 4 . We also demonstrated that the experimental magnetic hysteresis loop is in good agreement with the theoretical curve calculated by Stoner and Wohlfarth for a noninteracting randomly oriented uniaxial single-domain particle system. Moreover, we show that K is proportional to the cube of the saturation magnetization M s , which confirms earlier theoretical models for uniaxial magnets. V C 2012 American Institute of Physics. [http://dx

Structural inhomogeneities in FeTe0.6Se0.4: Relation to superconductivity

“…Although the analysis of the diffraction data may allow to assign a monoclinic structure of the inclusions, further analysis of our magnetization data are not entirely consistent since the monoclinic Fe 3 Se 4 is reported to be ferrimagnetic [40,44,45] with the magnetic transition temperature and hysteretic magnetization curve even above room temperature. Our magnetization measurements are hysteretic at low temperatures but do not indicate such a behavior for the SC sample at room temperature where only an S-shape is seen.…”

“…Our magnetization measurements are hysteretic at low temperatures but do not indicate such a behavior for the SC sample at room temperature where only an S-shape is seen. Moreover, the hysteretic magnetization curve of the SC sample has two-step character in contrast to a simple hysteresis found in Fe 7 Se 8 [44]. However, the magnetic properties of Fe 7 Se 8 are reported to be very sensitive to iron deficiency, causing vacancies ordered within the lattice.…”

FeSe2‐Decorated Bi2Se3 Nanosheets Fabricated via Cation Exchange for Chelator‐Free 64Cu‐Labeling and Multimodal Image‐Guided Photothermal‐Radiation Therapy

“…As far as the magnetic property of such composite-nanostructure is concerned, the absence of a hysteresis loop in the field-dependent magnetization measurement illustrated the superparamagnetic nature of FeSe 2 /Bi 2 Se 3 -PEG [17] (Supporting Figure S11). T2-weighted MR images of a series of concentrations of FeSe 2 /Bi 2 Se 3 -PEG solutions acquired by a 3T MR scanner revealed the concentration-dependent darkening effect (Figure 3C).…”

Grain boundary anisotropy on nano-polycrystalline magnetic thin films

“…It is important to stress that the temperature dependence of the anisotropy has been also considered in attention to experimental works reported [14][15][16] as well as the cubic anisotropy distortion on the surface and grain boundaries, where an important local structural disorder is expected. Studies obtained by ab-initio calculations and experimental processes have shown that the electronic configuration of the atoms belonging to these regions is significantly different respect to the extended and homogeneous crystalline medium in the core of the grains [17][18][19][20] .…”