Interrelation Between Structure and Magnetism of Ultra-Thin Mn Films Epitaxially Grown on (001) BCC Fe

1997 ◽  
Vol 475 ◽  
Author(s):  
S. Andrieu ◽  
Ph. Bauer ◽  
H. Fischer ◽  
M. Piecuch ◽  
M. Finazzi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Diffraction ◽  
Structural Transition ◽  
Magnetic Circular Dichroism ◽  
Magnetic Transition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
X Ray Absorption

ABSTRACTIn this paper, the interrelation between structural and magnetic properties of ultra-thin Mn films epitaxially grown on (001) bcc Fe is studied. The Mn growth and in-plane structure were controlled by electron diffraction (RHEED). The structures of the Mn films were determined by using X-Ray absorption spectroscopy (SEXAFS). Finally, the magnetic properties were studied by using X-Ray magnetic circular dichroïsm (XMCD). All the experiments were performed under ultra-high vacuum. As shown by XMCD experiments, a magnetic transition is observed at 2 Mn monolayers. The analysis of RHEED and SEXAFS experimental results clearly demonstrates that a structural transition comes with this magnetic transition.

The structural and magnetic properties of Sr-doped multiferroic CaMn7O12

2015 ◽  
Vol 29 (30) ◽  
pp. 1550221 ◽  
Author(s):  
Hong-Guang Zhang ◽  
Xiao-Chen Ma ◽  
Liang Xie
Keyword(s):  
Magnetic Properties ◽  
Raman Spectra ◽  
Magnetic Transition ◽  
Magnetic Interaction ◽  
Antiferromagnetic Order ◽  
Vibration Direction ◽  
Magnetic Transition Temperature ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
X Ray Absorption

The structural and magnetic properties of Sr-doped multiferroic [Formula: see text] were investigated by X-ray diffraction (XRD), Raman spectra, X-ray absorption spectroscopy and temperature dependence of magnetization. The XRD indicates that the samples are rhombohedral lattice (space group [Formula: see text]) with small additional phase [Formula: see text]. The refined lattice parameters of the main phase increases by the Sr doping. The Raman spectra demonstrate the phonon vibration direction is affected, which is probably due to the rotation of [Formula: see text] octahedral. However, as the valence state of Sr and Ca is same at +2, the samples with doping show nonvariation of peak position at Mn [Formula: see text] X-ray absorption spectra, indicating that the ratio of [Formula: see text] and [Formula: see text] ions is unchanged. And the magnetic transition temperature both at [Formula: see text] and [Formula: see text] is also not tunable because the amount of magnetic interaction between [Formula: see text] and [Formula: see text] is not influenced by doping Sr ion. Only the enhancement of the magnetization at low temperature is observed, which is the same as the effect caused by external magnetic fields. An unsaturated wasp-waist type hysteresis loop is observed, indicating the competition between ferromagnetic-like and antiferromagnetic order.

scholarly journals Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys

Nano Research ◽  
2021 ◽  
Author(s):  
Alevtina Smekhova ◽  
Alexei Kuzmin ◽  
Konrad Siemensmeyer ◽  
Chen Luo ◽  
Kai Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Circular Dichroism ◽  
Surface Region ◽  
Face Centered Cubic ◽  
X Rays ◽  
X Ray ◽  
High Entropy ◽  
X Ray Absorption ◽  
Absorption Edges

AbstractModern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2.3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.

ANNEALING EFFECT ON THE INDUCED MAGNETISM OF PLATINUM IN FePt NANOPARTICLES

2007 ◽  
Vol 21 (18) ◽  
pp. 1189-1196 ◽  
Author(s):  
F. WILHELM ◽  
A. ROGALEV ◽  
P. POULOPOULOS ◽  
M. ANGELAKERIS ◽  
J. TSIAOUSSIS ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Circular Dichroism ◽  
Annealing Effect ◽  
Fept Nanoparticles ◽  
X Ray ◽  
Remanence Ratio ◽  
Structural And Magnetic Properties ◽  
Coercivity Field ◽  
Average Size ◽  
Magnetic Circular Dichroism Spectra

Effect of annealing on structural and magnetic properties of non-equatomic chemically synthesized FePt nanoparticles with an average size of 3.2 nm diameter is reported. Annealing of the particles at 700°C resulted in the increase of particles size and the enhancement of total magnetization and coercivity, the latter could be attributed to a transformation from disordered to ordered crystallographic phase. Although the system is far from optimum "equatomic" stoichiometry, coercivity field of 1.1 kOe was obtained at 10 K together with remanence ratio of 0.55. X-ray magnetic circular dichroism spectra recorded at the Pt L 2,3 edges on annealed samples revealed the enhancement of magnetic moment induced on Pt atom.

scholarly journals The Determination of Interfacial Structure and Phase Transitions in Al/Cu and Al/Ni Interfaces by Means of Surface Extended X-Ray Absorption Fine Structure

1991 ◽  
Vol 238 ◽  
Author(s):  
E. V. Barrera ◽  
S. M. Heald
Keyword(s):  
Fine Structure ◽  
Room Temperature ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Interfacial Structure ◽  
Reaction Products ◽  
X Ray ◽  
Absorption Fine ◽  
Reaction Zones ◽  
X Ray Absorption

ABSTRACTSurface extended x-ray absorption fine structure (SEXAFS) was used to investigate the interfacial conditions of Al/Cu and Al/Ni shallow buried interfaces. Previous studies using glancing angle extended x-ray absorption fine structure, x-ray reflectivity, photoemission, and SEXAFS produced conflicting results as to whether or not the interfaces between Al and Cu and Al and Ni were reacted upon room temperature deposition. In this study polycrystalline bilayers of Al/Cu and Al/Ni and trilayers of Al/Cu/Al and Al/Ni/Al were deposited on tantalum foil at room temperature in ultra high vacuum and analyzed to evaluate the reactivity of these systems on a nanometer scale. It became overwhelming apparent that the interfacial phase reactions were a function of the vacuum conditions. Samples deposited with the optimum vacuum conditions showed reaction products upon deposition at room temperature which were characterized by comparisons to standards and by least squares fitting to be CuAl2 and NiAl3 respectively. The results of this study showed that the reacted zone thicknesses were readily dependent on the deposition parameters. For both Al on Cu and Al on Ni as well as the metal on Al conditions 10A reaction zones were observed. These reaction zones were smaller than that observed for bilayers of Al on Cu (30Å) and Al on Ni (60Å) where deposition rates were much higher and samples were much thicker. The reaction species are evident by SEXAFS, where the previous photoemission studies only indicated that changes had occurred. Improved vacuum conditions as compared to the earlier experiments is primarily the reason reactions on deposition were seen in this study as compared to the earlier SEXAFS studies.

scholarly journals The electronic and magnetic properties of strained La0.85Zr0.15MnO3films

2014 ◽  
Vol 70 (a1) ◽  
pp. C225-C225
Author(s):  
N. G. Deshpande ◽  
C. H. Weng ◽  
Y. F. Wang ◽  
Y. C. Shao ◽  
D. C. Ling ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Circular Dichroism ◽  
Magnetic Transition ◽  
Linear Dichroism ◽  
Orbital Ordering ◽  
Magnetic Transition Temperature ◽  
Edge Structure ◽  
X Ray ◽  
Electronic And Magnetic Properties

The electronic and magnetic properties of strained tetravalent-ion-doped La0.85Zr0.15MnO3 (LZMO) thin films that were epitaxially grown on SrTiO3 (STO) and MgO substrates were studied using temperature-dependent x-ray diffraction (XRD), x-ray absorption near-edge structure (XANES), x-ray linear dichroism (XLD) and x-ray magnetic circular dichroism (XMCD) at the Mn L3,2- and K-edge. XRD studies reveal that the LZMO thin films have compressive and tensile strains on the STO and MgO substrates, respectively. As temperature is reduced from room temperature to below magnetic transition temperature, the preferentially occupied Mn majority-spin eg orbital changes from the in-plane dx2-y2 to the out-of-plane d3z2-r2 orbital for LZMO/STO, and vice versa for LZMO/MgO. Experimental results suggest that the new hopping path that is mediated by the Mn2+ ions triggers a stronger d3z2-r2 orbital ordering of Mn3+ ions and enhances the ferromagnetic coupling between the Mn spin moments of t2g electrons in LZMO/STO, whereas the tensile strain stabilizes the dx2-y2 orbital by inducing lattice distortions of the MnO6 octahedra in LZMO/MgO.

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