Ultrafine particles of feroxyhyte (delta-FeOOH) have been studied by Mossbauer spectroscopy. Coating of the particles with oleic acid results in a decrease of the superparamagnetic blocking temperature, whereas pressing the particles with a uniaxial pressure of 1.3 GPa leads to an increase of the blocking temperature. The results suggest that the interaction between the ferrimagnetic particles leads to ordering of the magnetic moments below a critical temperature, which depends on the strength of the interaction. Measurements at 5 K in a large magnetic field show that the particles have a non-collinear spin structure. The degree of spin-canting increases with increasing strength of interactions. This suggests that the exchange interaction between surface iron atoms in neighbouring particles affects the canting.
|Title of host publication||Proc. ICAME'95|
|Place of Publication||Bologna|
|Publication status||Published - 1996|
|Event||International Conference on the Applications of the Mössbauer Effect - Rimini, Italy|
Duration: 10 Sep 1995 → 16 Sep 1995
|Conference||International Conference on the Applications of the Mössbauer Effect|
|Period||10/09/1995 → 16/09/1995|