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- Title
Electronic Structure and Magnetocaloric Effect of Sr-Doped SmCoO<sub>3</sub> Perovskites.
- Authors
Manh, T. V.; Pham, Y.; Phan, T. L.; Dang, N. T.; Tran, N.; Park, H. R.; Lee, B. W.; Yu, S. C.
- Abstract
We present a study on the magnetic and magnetocaloric characters of Sm1-xSrxCoO3 (x = 0.4–0.6) synthesized by solid-state reactions. Recorded M(T) data at H = 100 Oe show an increase of the Curie temperature (TC) from 143 K for x = 0.4 to 153 K for x = 0.5, but a higher x value (x = 0.6) reduces TC to ~ 92 K. A singularity region sandwiched between the Griffiths and pure paramagnetic phases has been observed in x = 0.4, but it becomes invisible at x = 0.5 and 0.6. These properties are assigned to a competition between ferromagnetic and anti-ferromagnetic interactions induced by Co3+ and Co4+ ions. The Co3+/Co4+ mixed valence has been confirmed upon the analysis of Co K-edge x-ray absorption spectra. Using Maxwell's relations and M(H) data, we have calculated the absolute magnetic entropy change (|∆Sm|). Around TC, the maximum magnetic entropy changes (|∆Smax|) of x = 0.4, 0.5 and 0.6 are about 1.19, 1.22 and 0.81 J/kg K for H = 50 kOe, respectively. The values of the relative cooling power are in the range of 58 ~ 93 J/kg. Our analyses also indicate all |∆Sm (T, H)| data obeying the universal master curve as constructing the |∆Sm|/|∆Smax| vs. θ plots, where θ is defined as the reduced temperature. When considering exponential parameters N(T, H) and n associated with |∆Sm(T, H)| and |∆Smax(H)|, respectively, we have found their values are different from the mean-field theory value n = 2/3. These results prove the Sm1-xSrxCoO3 samples have the second-order nature and short-range magnetic order.
- Subjects
MAGNETIC entropy; MAGNETOCALORIC effects; ELECTRONIC structure; X-ray absorption spectra; PEROVSKITE; CURIE temperature
- Publication
Journal of Electronic Materials, 2023, Vol 52, Issue 1, p177
- ISSN
0361-5235
- Publication type
Article
- DOI
10.1007/s11664-022-09943-7