Formation conditions of a magnetically ordered phase ɛ-Fe2O3. A FMR in situ study

The ferromagnetic resonance (FMR) method in situ is used to study the initial stages of the formation of ? iron oxide nanoparticles deposited on silica gel at temperatures up to 600°C. It is shown that at high-temperature treatment of starting samples obtained by impregnation with an iron(II) sulfate solution, supermagnetic ?-Fe₂O₃/SiO₂ nanoparticles form with a narrow size distribution. An analysis of the FMR data in comparison with the data of other methods enables the formulation of the formation conditions for systems of deposited ?-Fe₂O₃ nanoparticles without other polymorph impurities.     

Superproton phase transition in a K<Subscript>3</Subscript>H(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> crystal

The conductivity and heat capacity of tripotassium hydrogen trisulfate single crystals were studied. It was shown that these single crystals undergo a solid-solid phase transformation upon heating with the formation of new phases, and that their properties change considerably. Anomalies related to the sorption and desorption of water vapor were observed in the formed multiphase system. Such anomalies were observed for the first time in measurements of the true heat capacity.     

Intensity fluctuations during small-angle scattering of wave fields (review)

Conclusions In this review attention was mainly devoted to some general approaches and representations useful in the theory of small-angle scattering of waves primarily to evolution of predominant correlations, ray approximation, and classification of propagation modes. We would like to stress the significant commonality among particular problems. There are also some interesting possible analogies with other branches of physics, although they are actually beyound the scope of this review. Among the important problems not discussed here we must mention the problems of intensity fluctuations of fields at different frequencies, intensity fluctuations of pulsed rediation, small-angle scattering over paths with reflection, adaptive reception, etc. Material on these topics is presented in reviews [5, 26, 29, 38, 113] etc.Institute of Physics of Atmosphere, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 28, No. 5, pp. 535–565, May, 1985.     

Phase Transition in CsHSO4 Ferroelastic in a Magnetic Field

JETP Letters - A magnetically induced deceleration of the initial stage of the isothermal phase transition of ferroelastic-superprotonic cesium hydrogen sulfate has been detected. The effect is...     

Facile synthesis of nanosized ε-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> particles on the silica support

An approach is suggested to synthesize the ε-Fe₂O₃ particles supported on silica with the mean size of few nanometers, narrow size distribution and no admixture of any other iron oxide polymorphs. The facile synthesis is based on the pore filling impregnation method by iron sulfate (II) water solution with the following annealing procedure at ~1173 K. It is shown that the ε-Fe₂O₃ nanoparticles obtained are stable up to ~1173 K and possess superparamagnetic behavior up to ~870 K.