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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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Differential scanning calorimetry curves of BiCr0.9Ga0.1O3 measured at a heating/cooling rate of 10 K min−1 between 290 and 573 K. Results of three heating–cooling cycles are shown.
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Figure 2: Differential scanning calorimetry curves of BiCr0.9Ga0.1O3 measured at a heating/cooling rate of 10 K min−1 between 290 and 573 K. Results of three heating–cooling cycles are shown.

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
Differential scanning calorimetry curves of BiCr0.9Ga0.1O3 measured at a heating/cooling rate of 10 K min−1 between 290 and 573 K. Results of three heating–cooling cycles are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Differential scanning calorimetry curves of BiCr0.9Ga0.1O3 measured at a heating/cooling rate of 10 K min−1 between 290 and 573 K. Results of three heating–cooling cycles are shown.
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.