Effect of the itinerant electron density on the magnetization and Curie temperature of Sr 2 FeMoO 6 ceramics
The itinerant electron density ( n ) near the Fermi level has a close correlation with the physical properties of Sr 2 FeMoO 6 . Two series of single-phase Sr (2−y) Na y FeMoO 6 ( y = 0.1, 0.2, 0.3) and Sr (2−y) Na y Fe (1−x) Mo (1+x) O 6 ( y = 2 x ; y = 0.1, 0.2, 0.3) ceramics were specially design...
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| Published in | RSC advances Vol. 8; no. 51; pp. 29071 - 29077 |
|---|---|
| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
England
14.08.2018
|
| Online Access | Get full text |
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| Summary: | The itinerant electron density (
n
) near the Fermi level has a close correlation with the physical properties of Sr
2
FeMoO
6
. Two series of single-phase Sr
(2−y)
Na
y
FeMoO
6
(
y
= 0.1, 0.2, 0.3) and Sr
(2−y)
Na
y
Fe
(1−x)
Mo
(1+x)
O
6
(
y
= 2
x
;
y
= 0.1, 0.2, 0.3) ceramics were specially designed and the itinerant electron density (
n
) of them can be artificially controlled to be:
n
= 1 −
y
and
n
= 1 −
y
+ 3
x
= 1 + 0.5
y
, respectively. The corresponding crystal structure, magnetization and the ferromagnetic Curie temperature (
T
C
) of two subjects were investigated systematically. The X-ray diffraction analysis indicates that Sr
(2−y)
Na
y
FeMoO
6
(
y
= 0.1, 0.2, 0.3) have comparable Fe/Mo anti-site defect (ASD) content in spite of decreased
n
. However, a drastically improved Fe/Mo ASD can be observed in Sr
(2−y)
Na
y
Fe
(1−x)
Mo
(1+x)
O
6
(
y
= 2
x
;
y
= 0.1, 0.2, 0.3) caused by the intrinsic wrong occupation of normal Fe sites with excess Mo. Magnetization–magnetic field (
M
–
H
) behavior confirms that it is the Fe/Mo ASD not
n
that dominantly determines the magnetization properties. Interestingly, approximately when
n
≤ 0.9,
T
C
of Sr
(2−y)
Na
y
FeMoO
6
(
y
= 0.1, 0.2, 0.3) exhibits an overall increase with decreasing
n
, which is contrary to the
T
C
response in electron-doped SFMO. Such abnormal
T
C
is supposed to relate with the ratio variation of
n
(Mo)/
n
(Fe). Moreover, when
n
≥ 1,
T
C
of Sr
(2−y)
Na
y
Fe
(1−x)
Mo
(1+x)
O
6
(
y
= 2
x
;
y
= 0.3) exhibits a considerable rise of about 75 K over that of Sr
(2−y)
Na
y
Fe
(1−x)
Mo
(1+x)
O
6
(
y
= 2
x
;
y
= 0.1), resulting from improved
n
caused by introducing excess Mo into Sr
(2−y)
Na
y
FeMoO
6
. Maybe, our work can provide an effective strategy to artificially control
n
and ferromagnetic
T
C
accordingly, and provoke further investigation on the FeMo-baseddouble perovskites. |
|---|---|
| ISSN: | 2046-2069 2046-2069 |
| DOI: | 10.1039/C8RA05755A |