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 CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 59, 2017 

A publication of 

 
The Italian Association 

of Chemical Engineering 
Online at www.aidic.it/cet 

Guest Editors: Zhuo Yang, Junjie Ba, Jing Pan 
Copyright © 2017, AIDIC Servizi S.r.l. 
ISBN 978-88-95608- 49-5; ISSN 2283-9216 

Investigation of the Ferrimagnetic Transition in Doped 
Cobaltite Nd1-xSrxCoO3 (0.1≤x≤0.5) 

Yiyun Yang  

College of Electronics and Information Engineering, Ankang University, Ankang 725000, China 
yangyiyun@aku.edu.cn 

In the present study, the ferrimagnetic transition of doped cobaltite Nd1-xSrxCoO3 (0.1≤x≤0.5) was investigated 
in detail. The samples were successfully synthesized through solid state reaction method while the mixtures 
were ground and sintered. X-ray diffraction power patterns showed that all the samples were crystallized in the 
single perovskite structure with orthorhombic. Dc magnetization and ac susceptibility of samples were 
performed from 300 K to 5 K in the magnetic field. The results of dc magnetization measures suggest that Nd1-
xSrxCoO3 is ferrimagnetic phase below 60 K. The lower doping samples are well shown by a fit to the critical 
slowing down of the spin class. Moreover, the study shows that magnetic interaction appears between Co 
spins and Nd spins. Therefore, the investigation suggests that the Nd and Co anti-parallel, Nd1-xSrxCoO3 
ferrimagnetic transition exists at low temperature. Furthermore, in the paper we summarized the phase 
diagram obtains from the magnetic studies which presented the system is divided into ferromagnetic and spin- 
glass-like regions. 

1. Introduction 
In recent years, doped cobaltite Nd1-xSrxCoO3 (NSCO), have attracted wide spread attention due to the spin-
glass behavior which is inherent characteristics of phase separation system. Moreover, in order to study the 
properties of the doped compound, a lot of good research methods were adopted, which is successfully 
research in the areas. (Fondado et al., 2001; Ghoshray et al., 2004; Yang and Sui, 2010; Krimmel et al., 2001). 
Apart from this, Stauffer has reported the magnetic interaction of NSCO (Stauffer and Leighton, 2004), in 
which NSCO with x≤0.18 was reported as spin glass phase. At x=0.18 there exist an obvious change of the 
magnetization and the x>0.18 region was ferromagnetic behavior. A remarkable feature of the system is that 
its magnetic behavior changes with x in the spin-glass (SG) region which is very similar to that seen in the La1-
xSrxCoO3 samples (Nam et al., 1999; Joseph et al., 2005; Señarís-Rodríguez et al., 1999). For La1-xSrxCoO3 
system, a lot of investigations on magnetic behavior for the lower doping samples have been systematically 
reported (Mao et al., 2013; Huang et al., 2008), especially, for exchange bias phenomenon of the La1-
xSrxCoO3 (0.12≤x≤0.3) samples which was recently confirmed (Tang et al., 2006),

 but less study has been 
done about this phenomenon of Nd1-xSrxCoO3 system. Thus, further study about Nd1-xSrxCoO3 is very 
important in order to explore this system more clearly. In general, the research in this aspect is helpful to the 
development of magnetic electronics which is a general consensus now (Saron et al., 2016; Shirinova et al., 
2016; Wu et al., 2015). 
In this thesis, we study the dc magnetization and ac susceptibility of doped cobaltite Nd1-xSrxCoO3. Dc and ac 
magnetic properties data show region was named ferrimagnetic phase. 

2. Experiments 
2.1 Materials 

The high purity Nd2O3, SrCO3 and Co2O3 powders were prepared. In order to remove the moisture in the rare 
earth oxide Nd2O3, before prepared samples, we made thermogravimetric-differential thermal analysis (TG-
DTA) tests. TG-DTA tests were collected by the TG-DSC2960 instrument in the temperature range 20 °C-
1000 °C in the air. The test results (not shown here) show in the 280 °C and 420 °C appears obvious peak. 

                               
 
 

 

 
   

                                                  
DOI: 10.3303/CET1759161

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Please cite this article as: Yiyun Yang , 2017, Investigation of the ferrimagnetic transition in doped cobaltite nd1-xsrxcoo3 (0.1≤x≤0.5), 
Chemical Engineering Transactions, 59, 961-966  DOI:10.3303/CET1759161   

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And after 800 °C, the qualities of Nd2O3 remain unchanged. As a result, the Nd2O3 were precalcined at 800 °C 
in the air. 

20 30 40 50 60 70

 

 

2θ ( °  )

x=0.2

 

 

In
e
n
si

ty
(A

rb
.U

n
its

)

x=0.15

 

 

x=0.1

(2
0
0
)

(2
1
0
)

(0
0
2

)

(3
0
0
)

(1
1

2
)

(2
2
0
) (0

2
2

)
(1

2
2
)

(0
3

1
)

(1
1

3
)

(2
3
1
)

(3
3

1
)

(0
4

0
)

20 30 40 50 60 70

 

 

 

x=0.3

2θ ( °  )

  

 x=0.5
In

e
n

si
ty

(A
rb

.U
n

its
)

 

x=0.4

  

Figure 1: The room temperature X-ray diffraction pattern of Nd1-xSrxCoO3 (0.1≤x≤0.5) 

2.2 Synthesis of Nd1-xSrxCoO3 samples 

The doped cobaltite NSCO samples were synthesized by solid state reaction method. First, a certain 
proportion of Nd2O3, Co2O3 and SrCO3 were ground and sintered at 1000 °C. After that, the mixture was 
reground and pressed into pellets in 8 Mpa pressure and fired at 1100 °C and 1200 °C for 24h, respectively. 
The last, along with the furnace cooling to room temperature, complete the preparation of the samples. 

2.3 Characterization techniques 

X-ray diffraction (XRD) power patterns were measured through the Bede D1 XRD spectrometer. The 
magnetization testing was made by the physical properties measurement system (PPMS) in field cooled 
process (FC) and in a larger temperature range. Ac susceptibility measurements were collected in the 
frequency range 10 Hz<f<10 kHz and the same temperature range as dc measurement. 

3. Results and discussion 
3.1 Dc magnetization 

X-ray diffraction power patterns in Figure 1 present the absence of impurity phases, which was indicated that 
the samples were crystallized in the single perovskite structure with orthorhombic. 
In Figure 2 are the dc magnetization measured in a static field after FC. With increasing x, dc magnetization 
increase in magnitude. It can be seen clearly from the figure that the samples increase in the magnetization 
below Curie temperature TC. This means when field cooled the cluster align, leading to the onset of large 
ferromagnetic-type magnetization. These results are consistent with those described in La1-xSrxCoO3 samples 
(Nam et al., 1999; Joseph et al., 2005). In the FM region, the TC monotonously increases with x. 
A maximum of magnetization for Nd0.90Sr0.10CoO3 sample was obtained at low temperature, but not visible for 
else samples. Kriener el at pointed out this feature in La1-xSrxCoO3 (Kriener et al., 2004). Such as x≥0.15, due 
to the effect of Nd3+ spins, magnetization decrease in low temperature as shown in the figure. Krimmel 
observed this phenomenon in Nd0.67Sr0.33CoO3 cobaltite (Krimmel et al., 2001). Because of Co

3+/Co4+and Nd3+ 
magnetic moment in reverse order, which cause the ferrimagnetic transition. The Nd ions are induced via the 
Co moments, but the Nd moments are aligned anti-parallel to the field created by the Co moments and some 
Nd-Co magnetic interaction must be invoked. The ferrimagnetic transition appears only at low temperature, 
because of the weak interaction between Co3+/Co4+ and Nd3+ magnetic moment. Moreover, ferrimagnetic 

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temperature (TFerri) of the samples increase with x, due to the strong coupling of Nd and Co spin as a result of 
increase of the number of ferromagnetic clusters. 

0 50 100 150 200 250 300

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

 

M
(
u

B
/f

.u
.)

T (K) 

 x=0.10

 x=0.15

 x=0.20

 x=0.30

 x=0.40

 

Figure 2: Field cooled magnetization of Nd1-xSrxCoO3 (0.1≤x≤0.4), measured in the field 1000 Oe  

0 . 2

0 . 3

0 . 4

0 . 5

0 . 6

0 . 7

0 4 0 8 0 1 2 0 1 6 0 2 0 0 2 4 0
0

1

2

3

4

5

- 0 . 6 3 - 0 .6 0 - 0 . 5 7 - 0 . 5 4 - 0 . 5 1 - 0 .4 8 - 0 . 4 5 - 0 . 4 2

2 . 7

3 . 0

3 . 3

3 . 6

3 . 9

4 . 2
 

 

lo
g 1

0(
f)

l o g 1 0 ( ( T f- T S G ) / T S G )

 

 

  

x = 0 .1

 f = 5 1 H z
 f = 5 0 2 H z
 f = 1 0 0 1 H z
 f = 5 0 0 2 H z
 f = 9 9 9 7 H z

  

x = 0 .2

- 2 .2 -2 .1 -2 .0 -1 .9 -1 .8 -1 .7 -1 .6
1 .5

2 .0

2 .5

3 .0

3 .5

4 .0

 

 

lo
g

1
0
(f

)

l o g 1 0 ( ( T f- T S G ) /T S G )

T ( K )

χ'
(e

m
u

/m
o
le
)

  

Figure 3: The ac susceptibility of x=0.1, 0.2 sample. Inset fit of ac susceptibility with the critical slowing down 

3.2 Ac susceptibility 

In order to understand the magnetization further, ac susceptibility was collected at difference frequencies. Due 
to the magnetic moments were frozen at frozen temperature Tf, ac susceptibility curve peaks change with 
frequency. In Figure 3 presents respectively the ac susceptibility of x=0.1, 0.2 and 0.4. The x=0.1, 0.2 are spin 
glass (SG), however, from the χ ′ (T) curve we concluded that x=0.4 is the FM behavior (Nam et al., 1999; 
Krimmel et al., 2001). 
In Figure 3 the ac susceptibility peaks change significantly with frequency of x=0.1 which appears at Tf. As we 
known that this behavior is the important feature of SG phase (Bianco et al., Yang, 2014; 2004; Gruyters, 
2005; Caiuffo et al., 1999; Passamani, et al., 2006). Different with the x=0.1 sample, then, for x=0.20 simple 
present some weak frequency dependent peaks. This frequency-dependent for x=0.10 and x=0.20 is similar 
qualitatively to that describe for La1-xSrxCoO3 and Gd1-xSrxCoO3 (Señarís-Rodríguez et al., 1999; Rey-
Cabezudo, et al., 2002; Luo, et al., 2006; Li, et al., 2016). We assume the x=0.2 sample is cluster glass (CG) 
due to present a small dc magnetization and the weak frequency dependent peaks. The presence of the 

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typical features of spin-glass state in NSCO was well revealed by ac susceptibility. The ac susceptibility of 
x=0.4 sample is a decrease with decreasing of temperature which shows frequency independent peak. The 
peak, not changed with frequency at Curie temperature, marks the beginning of the ferromagnetic order. The 
difference of the χ ′ (T) between x=0.20 and x=0.4 sample indicated that the number of ferromagnetic clusters 
increase in higher doped sample. In general, the tests of ac susceptibility make us understand internal 
mechanism of the freezing dynamics. 
The ac susceptibility data of the lower doping samples are well shown by a fit to the critical slowing down of 
the spin class. These properties are performed with the following equation:  

τ τ0 f SG SG -zν= [( - )/T ]T T  (1) 

Table 1: The fitted parameters of Eq. 1 while fitted with ac susceptibility 

Slowing down model  τ0 (s) ΖV TSG (K) 

x=0.1 3.1(6)×10-10 9.3(9) 12.3(1) 

x=0.15 1.6(9)×10-12 10.8(5) 35.1(5) 

x=0.2 6.0(6)×10-11 4.0(2) 72.0(6) 

The best fit, for example x=0.1 and 0.2 sample, which are displayed in inset of Figure 3. 

0 50 100 150 200 250 300

0

3

6

9

12

x=0.4

160 165 170 175 180

4

6

8

10

χ'
(e

m
u
/m

o
le
)

 

T(K)

χ'
(e

m
u

/m
o

le
)  f=51Hz

 f=502Hz
 f=1001Hz
 f=5002Hz
 f=9997Hz 

T(K)
 

Figure 4: Temperature dependence of the real part of the ac susceptibility of x=0.4 sample 

3.3 Phase diagram 

Chapter 2 From what has been discussed above, in Figure 5 we summarized the phase diagram obtain from 
the magnetic studies. The phase diagram presented here is divided into two regions. As is shown, below 
x≤0.2 the magnetic properties are dominated by the spin glass or cluster glass. In this region, the dc and ac 
susceptibility show features which are typical spin glass/cluster glass behavior and the frozen temperature Tf 
strongly increases with x. We emphasized that additional anomalous feature in ac susceptibility curves for 0.2, 
which has been observed in polycrystalline Gd1-xSrxCoO3 system (Luo, et al., 2006), occur in our sample. 
Thus, we conclude that the x=0.2 sample is not spin glass but is cluster glass. Above x=0.2, the doped 
cobaltite system becomes ferromagnetic properties and presents ferrimagnetic properties below 60 K. 
Furthermore, the temperature of ferrimagnetic transition shows some remarkable characteristics. As is shown 
in the figure 5, the temperature of ferrimagnetic transition increases with x and tends to saturate around 60 K 
for larger x. Our results agree with that obtained by Neutron power diffraction in the literature (Krimmel et al., 
2001; Paraskevopoulos, et al., 2001). 

 

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0.1 0.2 0.3 0.4 0.5
10

20

30

40

50

60

70

80
T

 (
K

)

X 

 TSG

 TFerri

Ferri

SG / CG

 

Figure 5: Ferrimagnetic (Ferri) and spin/cluster glass (SG/CG) phase diagram of Nd1-xSrxCoO3. The solid lines 
are to guide the eye 

4. Conclusions 
To conclude, we have measured and analyzed the magnetization data of NSCO over a wide range of doping. 
The detailed research was performed on the Nd1-xSrxCoO3 (0.1≤x≤0.2) which is typical spin or cluster-glass 
behavior. Moreover, for x>0.2 samples, the system become ferromagnetic and show ferrimagnetic properties 
below 60 K. The Curie temperature TC increases with x up to 0.5. Thus, the investigation suggests that the 
magnetic moment of Nd and Co in reverse order, Nd1-xSrxCoO3 ferrimagnetic transition exists at the low 
temperature. 

Acknowledgments  

The work is supported by the Special Scientific Research Program Funded of Ankang University (Program No. 
2015AYPYZR05), Project from Scientific Research Fund of Shaanxi Provincial Education Department (Grant 
No. 16JK1015) 

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