Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 11, pp. 1915−1918.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
Nguen Anh Tien, I.Ya. Mittova, O.V. Al’myasheva, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 11, pp. 1766−1769.
INORGANIC SYNTHESIS AND INDUSTRIAL
Inﬂ uence of the Synthesis Conditions on the Particle Size
and Morphology of Yttrium Orthoferrite Obtained
from Aqueous Solutions
Nguen Anh Tien
, I. Ya. Mittova
, and O. V. Al’myasheva
Voronezh State University, Voronezh, Russia
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received October 6, 2009
Abstract—The size and morphology of yttrium orthoferrite nanoparticles were examined in relation to the
synthesis conditions. The chemical composition of the crystalline phases resulted from heat treatment of the
samples at 650°С varies with the procedure of coprecipitation of yttrium and iron(III) hydroxides. At the same
time, heat treatment at 750°С leads to formation of yttrium orthoferrite solely. The size of the YFeO
weakly dependent on the initial composition preparation procedure, and the size and shape of their agglomerates
are sensitive to the conditions of coprecipitation of the hydroxides.
Nanosized objects have attracted increased research
interest owing to unusual physical and chemical properties
as compared to their macrosized analogs [1–5].
Complex oxides are extensively used in preparation
of structural and functional materials intended for
diverse applications [6–9]. Among them, perovskite-type
oxides represent one of the most promising classes of
compounds. On the one hand, they offer a broad range
of practically signiﬁ cant properties [6, 10, 11], and, on
the other, hold promise for basic research applications
owing to high sensitivity of their properties to reduction
of the particle size to the nanometer scale.
In preparation of ferromagnetic oxide materials, of
much signiﬁ cance are the chemical methods by which
the components are homogenized to afford high chemical
uniformity and activity of the powders in phase formation
[12, 13], In this context, much promise is offered by
methods utilizing coprecipitation of the initial substances
from aqueous solutions .
In view of the above, we examined here the particle
size and morphology of yttrium orthoferrite prepared
by dehydration of coprecipitated yttrium and iron(III)
hydroxides in relation to the synthesis conditions.
Yttrium orthoferrite was prepared by coprecipitation
with an aqueous solution of analytically pure-grade
ammonium hydroxide from an equimolar mixture of 0.5
M solutions of chemically pure-grade yttrium chloride
and iron(III) chloride hexahydrates. The solutions were
prepared immediately before precipitation.
The properties of the materials prepared from the
precursors synthesized by coprecipitation from solutions
are known to be strongly dependent on the synthesis
conditions [13–15]. Therefore, we proposed two
procedures for preparation of yttrium orthoferrite.
(1) An equimolar mixture of YCl
was added to boiling water under permanent stirring and
boiled for 3–5 min, during which period the solution
acquired a red-brown color being retained during
subsequent cooling. The resulting sol was cooled to room
temperature, after which an aqueous ammonia (0.5 wt %)
was added slowly in the amount required for exhaustive
precipitation of yttrium and iron hydroxides.
(2) Coprecipitation from an equimolar mixture
of yttrium and iron chlorides was carried out using
aqueous ammonia in a manner similar to that described