Ho, Thi Anh and Phan, The Long and N., V. Quang and S., L. Cho and S., C. Yu
(2019)
Short and long range ordering in La1−xSrxCoO3 cobaltites.
Journal of Magnetism and Magnetic Materials, 477
.
pp. 396-403.
ISSN 03048853
Abstract
We have carefully studied the relation between the critical and electrical behavior of rhombohedral
La1 -xSrxCoO3 (x = 0.2-0.5) compounds prepared by solid-state reactions. The results obtained from
analyzing M(T, H) data indicate that and all compounds undergo a second-order phase transition
and the ferromagnetic-paramagnetic (FM-PM) transition temperature increase from approximate
182 K for x = 0.2 to 253 K for x = 0.5. Basing on the modified Arrott and Kouvel-Fisher techniques,
scaling hypothesis, and critical isotherm analysis, we have determined the critical exponent values
characteristic of magnetic order of La1 -xSrxCoO3, with = 0.361~0.489, = 1.021~1.346, and =
2.99~4.72. Interestingly, though all compounds are metallic ferromagnets, we have found the phase
segregation in magnetic order as x > 0.3, where magnetic interactions tend to change from long-toshort-range FM order together with the absence of the insulating-like behavior at temperatures
below 100 K. These phenomena are related to the spatial coexistence of multiple electronic and
magnetic phases due to the changes in concentration of cobalt ions, spin-state transitions, and the
existence of poor-hole anti-FM and hole-rich FM regions.
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