scholarly journals Spin relaxation in antiferromagnetic Fe–Fe dimers slowed down by anisotropic DyIII ions

2013 ◽  
Vol 4 ◽  
pp. 807-814 ◽  
Author(s):  
Valeriu Mereacre ◽  
Frederik Klöwer ◽  
Yanhua Lan ◽  
Rodolphe Clérac ◽  
Juliusz A Wolny ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Magnetic Anisotropy ◽  
Hyperfine Field ◽  
Crystal Field ◽  
Spin Relaxation ◽  
Mossbauer Spectroscopy ◽  
Molecular Clusters ◽  
Hyperfine Fields ◽  
Mößbauer Spectroscopy

By using Mössbauer spectroscopy in combination with susceptibility measurements it was possible to identify the supertransferred hyperfine field through the oxygen bridges between DyIII and FeIII in a {Fe4Dy2} coordination cluster. The presence of the dysprosium ions provides enough magnetic anisotropy to “block” the hyperfine field that is experienced by the iron nuclei. This has resulted in magnetic spectra with internal hyperfine fields of the iron nuclei of about 23 T. The set of data permitted us to conclude that the direction of the anisotropy in lanthanide nanosize molecular clusters is associated with the single ion and crystal field contributions and 57Fe Mössbauer spectroscopy may be informative with regard to the the anisotropy not only of the studied isotope, but also of elements interacting with this isotope.

Sn hyperfine field systematics in Rh2MnZ Heusler alloys

1984 ◽  
Vol 62 (4) ◽  
pp. 396-399 ◽  
Author(s):  
R. A. Dunlap ◽  
S. Jha ◽  
G. M. Julian
Keyword(s):  
Mössbauer Spectroscopy ◽  
Hyperfine Field ◽  
Electron Density ◽  
Conduction Electron ◽  
Mossbauer Spectroscopy ◽  
Heusler Alloys ◽  
Hyperfine Fields ◽  
Mößbauer Spectroscopy ◽  
Theoretical Predictions ◽  
Conduction Electron Density

Sn hyperfine fields were measured using Mössbauer spectroscopy in the Heusler alloys Rh2MnZ (Z = Ge, Sn). The measurements yielded values of −48 and +31 kOe at 77 K for Sn in Rh2MnGe and Rh2MnSn, respectively. These values showed that in these alloys the Sn hyperfine field decreases with increasing conduction electron density. These results are compared with those obtained for Sn hyperfine fields in X2MnZ and Co2YZ Heusler alloys and are discussed in terms of theoretical predictions.

Measurement of Extreme Hyperfine Fields in Two-Coordinate High-Spin Fe2+Complexes by Mössbauer Spectroscopy: Essentially Free-Ion Magnetism in the Solid State

2014 ◽  
Vol 53 (22) ◽  
pp. 12100-12107 ◽  
Author(s):  
Aimee M. Bryan ◽  
Chun-Yi Lin ◽  
Michio Sorai ◽  
Yuji Miyazaki ◽  
Helen M. Hoyt ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Solid State ◽  
High Spin ◽  
Mossbauer Spectroscopy ◽  
Hyperfine Fields ◽  
Mößbauer Spectroscopy ◽  
Free Ion

Mössbauer spectra of α- and γ-polymorphs of FeOOH and Fe2O3 : effects of poor crystallinity and of Al-for-Fe substitution

Clay Minerals ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 591-606 ◽  
Author(s):  
E. De Grave ◽  
C. A. Barrero ◽  
G. M. Da Costa ◽  
R. E. Vandenberghe ◽  
E. Van San
Keyword(s):  
Mössbauer Spectroscopy ◽  
Mössbauer Spectra ◽  
Mossbauer Spectroscopy ◽  
Precise Determination ◽  
Zero Field ◽  
Hyperfine Fields ◽  
Morin Transition ◽  
Mossbauer Spectra ◽  
Al Content ◽  
Mößbauer Spectroscopy

AbstractThis paper presents various aspects, revealed by Mössbauer spectroscopy, of structural and magnetic properties of Al-substituted small-particle soil-related oxides. For goethite we focus on the relations between the hyperfine fields on the one hand, and crystallinity and Al content on the other. It is argued that these relations only provide a rough estimate of the Al content in natural samples. The ferrimagnetic-like behaviour reflected in the external-field Mössbauer spectra (4.2 K, 60 kOe) of certain Al goethites is presented. The spectra obtained for lepidocrocites are not spectacular, but confirmed that up to ∼10 at.% Al can be incorporated in the structure. Three differently-made series of hematites are considered. The Morin transition and spin structures in hematite are very sensitive to crystallinity and Al content, and probably to the presence of structural OH–. Integral low-energy electron Mössbauer spectroscopy on non-substituted samples indicates that the Morin-transition temperature in the surface layers (2 to 5 nm) is not significantly shifted from the bulk value. Measurements in extremely high magnetic fields (140 kOe) have shown that a spin-flip transition is induced in highly-substituted samples which exhibit no Morin transition in zero field. The use of external fields is crucial for the characterization and precise determination of the hyperfine parameters and site occupancies for maghemites, and for phase analyses of magnetic soils.

Sign in / Sign up

Export Citation Format

Share Document