Structural, magnetic, magnetocaloric and critical behaviour of La0.67Ba0.22Sr0.11Mn0.95Ti0.05O3 nanopowder

In this paper, we studied the effect of Ti doping on the structural, magnetic and magnetocaloric properties of the compound La0.67Ba0.22Sr0.11Mn0.95Ti0.05O3 synthesized by the solid-solid method. The structural properties were examined by a Siemens D5000 diffractometer, and the magnetic properties were determined using a SQUID magnetometer. The developed sample crystallized in the orthorhombic system with the space group Pnma. The Rietveld refinement of the X-ray nanopowder data certifies this finding. The unit cell volume decreased significantly while doping, this behaviour can be explained by the deformation of the lattice and changes in the lengths and angles of the bonds between the B-site ions and oxygen ions. The magnetization measurements indicate that the studied nanopowder has a transition from the paramagnetic state to the ferromagnetic state. Magnetocaloric measurements show a change in entropy (- Delta S-M) near the Curie temperature. The maximum of the magnetic entropy decreased with the substitution Ti from 2.75 the mother sample to 0.7417 J kg(-1) K-1 the studied sample. Our results on magnetocaloric properties suggest that the studied sample La0.67Ba0.22Sr0.11Mn0.95Ti0.05O3 might be a possible material for magnetic refrigeration around room temperature. The appreciated critical exponents beta, gamma and delta were determined from the modified Arrott graphs. The Kouvel-Fisher method indicated that the behaviour of the developed sample is consistent with the mean-field model. However, the critical exponent beta and the critical exponent gamma are related to mean-field theory.

Automated summary

The study investigates the effects of Ti doping on the structural, magnetic, and magnetocaloric properties of the compound La0.67Ba0.22Sr0.11Mn0.95Ti0.05O3. The developed sample showed changes in crystal structure and magnetic behavior, indicating potential for magnetic refrigeration around room temperature. The critical exponents determined from the modified Arrott graphs suggest consistency with mean-field theory in the developed sample.