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Magnetic properties of solid solutions between BiCrO 3 and BiGaO 3 with perovskite structures

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ABSTRACT

Magnetic properties of BiCr1−xGaxO3 perovskite-type solid solutions are reported, and a magnetic phase diagram is established. As-synthesized BiCrO3 and BiCr0.9Ga0.1O3 crystallize in a monoclinic (m) C2/c structure. The Néel temperature (TN) decreases from 111 K in BiCrO3 to 98 K in BiCr0.9Ga0.1O3, and spin-reorientation transition temperature increases from 72 K in BiCrO3 to 83 K in BiCr0.9Ga0.1O3. o-BiCr0.9Ga0.1O3 with a PbZrO3-type orthorhombic structure is obtained by heating m-BiCr0.9Ga0.1O3 up to 573 K in air; it shows similar magnetic properties with those of m-BiCr0.9Ga0.1O3. TN of BiCr0.8Ga0.2O3 is 81 K, and TN of BiCr0.7Ga0.3O3 is 63 K. Samples with x = 0.4, 0.5, 0.6 and 0.7 crystallize in a polar R3c structure. Long-range antiferromagnetic order with weak ferromagnetism is observed below TN = 56 K in BiCr0.6Ga0.4O3, TN = 36 K in BiCr0.5Ga0.5O3 and TN = 18 K in BiCr0.4Ga0.6O3. BiCr0.3Ga0.7O3 shows a paramagnetic behaviour because the Cr concentration is below the percolation threshold of 31%.

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Portions of experimental x-ray powder diffraction patterns of (a) m-BiCr0.9Ga0.1O3 and (b) o-BiCr0.9Ga0.1O3 measured with the CuKα radiation at room temperature in the logarithmic scale to emphasize the difference in weak reflections. Possible Bragg positions are indicated by tick marks for the main perovskite phases and Bi2O2CO3 and Cr2O3 impurities.
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Figure 3: Portions of experimental x-ray powder diffraction patterns of (a) m-BiCr0.9Ga0.1O3 and (b) o-BiCr0.9Ga0.1O3 measured with the CuKα radiation at room temperature in the logarithmic scale to emphasize the difference in weak reflections. Possible Bragg positions are indicated by tick marks for the main perovskite phases and Bi2O2CO3 and Cr2O3 impurities.

Mentions: m-BiCr0.9Ga0.1O3 exhibits a structural phase transition and shows a peak on the DSC curve at about 500 K on heating, and at 480 K on cooling. After heating as-synthesized m-BiCr0.9Ga0.1O3 up to 573 K, its XRD pattern changes. All fundamental perovskite reflections remain the same; however, weak superstructure reflections change. Reflections can be indexed in the PbZrO3-related structure [21] with space group Pnma and lattice parameters of a = 5.4892(4) Å, b = 15.4761(9) Å and c = 11.1269(7) Å (figure 3); this sample will be called o-BiCr0.9Ga0.1O3. Irreversible transformations of high-pressure phases were also found, for example, in BiFe0.5Sc0.5O3 [22]. The origin of the irreversible behaviour is the existence of competing phases.


Magnetic properties of solid solutions between BiCrO 3 and BiGaO 3 with perovskite structures
Portions of experimental x-ray powder diffraction patterns of (a) m-BiCr0.9Ga0.1O3 and (b) o-BiCr0.9Ga0.1O3 measured with the CuKα radiation at room temperature in the logarithmic scale to emphasize the difference in weak reflections. Possible Bragg positions are indicated by tick marks for the main perovskite phases and Bi2O2CO3 and Cr2O3 impurities.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036460&req=5

Figure 3: Portions of experimental x-ray powder diffraction patterns of (a) m-BiCr0.9Ga0.1O3 and (b) o-BiCr0.9Ga0.1O3 measured with the CuKα radiation at room temperature in the logarithmic scale to emphasize the difference in weak reflections. Possible Bragg positions are indicated by tick marks for the main perovskite phases and Bi2O2CO3 and Cr2O3 impurities.
Mentions: m-BiCr0.9Ga0.1O3 exhibits a structural phase transition and shows a peak on the DSC curve at about 500 K on heating, and at 480 K on cooling. After heating as-synthesized m-BiCr0.9Ga0.1O3 up to 573 K, its XRD pattern changes. All fundamental perovskite reflections remain the same; however, weak superstructure reflections change. Reflections can be indexed in the PbZrO3-related structure [21] with space group Pnma and lattice parameters of a = 5.4892(4) Å, b = 15.4761(9) Å and c = 11.1269(7) Å (figure 3); this sample will be called o-BiCr0.9Ga0.1O3. Irreversible transformations of high-pressure phases were also found, for example, in BiFe0.5Sc0.5O3 [22]. The origin of the irreversible behaviour is the existence of competing phases.

View Article: PubMed Central - PubMed

ABSTRACT

Magnetic properties of BiCr1−xGaxO3 perovskite-type solid solutions are reported, and a magnetic phase diagram is established. As-synthesized BiCrO3 and BiCr0.9Ga0.1O3 crystallize in a monoclinic (m) C2/c structure. The Néel temperature (TN) decreases from 111 K in BiCrO3 to 98 K in BiCr0.9Ga0.1O3, and spin-reorientation transition temperature increases from 72 K in BiCrO3 to 83 K in BiCr0.9Ga0.1O3. o-BiCr0.9Ga0.1O3 with a PbZrO3-type orthorhombic structure is obtained by heating m-BiCr0.9Ga0.1O3 up to 573 K in air; it shows similar magnetic properties with those of m-BiCr0.9Ga0.1O3. TN of BiCr0.8Ga0.2O3 is 81 K, and TN of BiCr0.7Ga0.3O3 is 63 K. Samples with x = 0.4, 0.5, 0.6 and 0.7 crystallize in a polar R3c structure. Long-range antiferromagnetic order with weak ferromagnetism is observed below TN = 56 K in BiCr0.6Ga0.4O3, TN = 36 K in BiCr0.5Ga0.5O3 and TN = 18 K in BiCr0.4Ga0.6O3. BiCr0.3Ga0.7O3 shows a paramagnetic behaviour because the Cr concentration is below the percolation threshold of 31%.

No MeSH data available.