Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11008823 | Current Applied Physics | 2018 | 26 Pages |
Abstract
Magnetization versus temperature and magnetic-field measurements, M(T, Ha), have been carried out to study the magnetic and critical properties of polycrystalline La1-xBaxCoO3 (xâ¯=â¯0.3 and 0.5) cobaltites. These compounds with the density of â¼6.2â¯g/cm3 crystallized in the R3¯c rhombohedral and Pm3¯m cubic structures, respectively. With an applied field Haâ¯=â¯200â¯Oe, M(T) data have revealed that the samples with xâ¯=â¯0.3 and 0.5 exhibit the ferromagnetic-paramagnetic (FM-PM) phase transition at the Curie temperature points TCâ¯=â¯202 and 157â¯K, respectively. At 4.2â¯K, the saturation magnetization (Msat) decreases from 35.9 emu/g for xâ¯=â¯0.3-26.1 emu/g for xâ¯=â¯0.5. Particularly, the critical-behavior analyses in the vicinity of TC reveal all samples undergoing a second-order phase transition, with critical exponent values (βâ¯=â¯0.328 and γâ¯=â¯1.251 for xâ¯=â¯0.3, and βâ¯=â¯0.331 and γâ¯=â¯1.246 for xâ¯=â¯0.5) close to those expected for the 3D Ising model. This proves short-range magnetic order existing in La1-xBaxCoO3. We believe that magnetic inhomogeneities due to the mixture of hole-rich FM regions (confined in the trivalent-cobalt hole-poor anti-FM matrix) and uniaxial anisotropy prevent long-range order in La1-xBaxCoO3.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Phan The Long, Dimitar N. Petrov, J. Äwik, N.T. Dang, Viet Dongquoc,