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Crystal and magnetic structure in co-substituted BiFeO3
Izabela Sosnowska1, Masaki Azuma, Radosław Przeniosło
1Institute of Experimental Physics, Physics Faculty, University of Warsaw , Hoża 69, 00-681 Warsaw, Poland.
Inorganic Chemistry
|November 5, 2013
Summary
Bismuth iron cobalt oxide exhibits a magnetic structure transition from cycloidal to collinear antiferromagnetic upon heating. This transition is linked to changes in its crystal structure from rhombohedral to monoclinic phases.
Area of Science:
- Materials Science
- Solid State Physics
- Crystallography
Background:
- Bismuth ferrite (BiFeO3) is a multiferroic material with potential applications in data storage and spintronics.
- Doping BiFeO3 with other transition metals, such as cobalt (Co), can modify its magnetic and structural properties.
- Understanding the interplay between crystal structure and magnetic ordering is crucial for designing advanced functional materials.
Purpose of the Study:
- To investigate the magnetic and crystal structure transitions in cobalt-doped bismuth ferrite, specifically BiFe(0.8)Co(0.2)O3.
- To elucidate the relationship between the cycloidal and collinear antiferromagnetic phases and the underlying crystal symmetry.
- To provide a detailed structural and magnetic characterization of BiFe(0.8)Co(0.2)O3 across a range of temperatures.
Main Methods:
- Ultra-high-resolution neutron diffraction was employed to probe the magnetic and crystal structures.
- Temperature-dependent studies were conducted from 10 K to 573 K.
- Analysis of neutron diffraction intensities was performed to model the magnetic moment arrangements and crystal symmetries.
Main Results:
- A transition from a cycloidal space-modulated spin structure at 10 K to a collinear G-type antiferromagnetic structure at 120 K was observed.
- The magnetic structure is well-described by antiparallel Fe(3+) and Co(3+) magnetic moments.
- The crystal structure transforms from rhombohedral (R3c) to monoclinic (Cm) upon heating above room temperature, with the Cm phase being dominant at 573 K.
- A collinear C-type antiferromagnetic structure was identified in the annealed monoclinic Cm phase at room temperature.
Conclusions:
- Cobalt doping in BiFeO3 induces significant changes in both magnetic and crystal structures.
- The observed magnetic transitions are strongly coupled to the crystallographic phase changes.
- BiFe(0.8)Co(0.2)O3 presents a tunable multiferroic system with distinct magnetic phases dependent on temperature and thermal history.
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