Above room temperature magnetic entropy in non-stoichiometric manganese of La0.67Sr0.33MnO3 manganites

Investigation on the structural, magnetic, magnetocaloric and magnetotransport behaviour of La0.7Sr0.3MnO3 manganites synthesised by different routes

“…According to Franco et al, 67,70 the critical exponents have been determined from the field dependency of the MCE. In materials with second order phase transitions, the field dependency of the magnetic entropy change can be stated using eqn (12) given by…”

“…16 Perovskite manganese oxides of the form R 1Àx A x MnO 3 (R = trivalent rare earth ion, A = divalent alkaline earth ion) have received wide attention recently due to their exceptional magnetic and electrical characteristics and the close proximity between their spin, charge, orbital, and lattice degrees of freedom. 4,12,17,18 CMR refers to a drastic change in the electrical resistance of a material under the influence of an external magnetic field.…”

“…Transition metal oxides display a staggeringly wide range of physical phenomena, such as multiferroicity, 1 colossal magnetoresistance (CMR), 2–7 high temperature superconductivity, 8,9 and magnetocaloric effect (MCE), 10–12 as cathode materials in solid oxide fuel cells 13 and can have unique applications in spintronics 14,15 as well as in hyperthermia applications. 16 Perovskite manganese oxides of the form R 1− x A x MnO 3 (R = trivalent rare earth ion, A = divalent alkaline earth ion) have received wide attention recently due to their exceptional magnetic and electrical characteristics and the close proximity between their spin, charge, orbital, and lattice degrees of freedom.…”

Evidence of a Large Refrigerant Capacity in Nb-Modified La1.4Sr1.6Mn2−xNbxO7 (0.0 ≤ x ≤ 0.15) Layered Perovskites

“…This may lead to distortions in the crystal lattice, influencing the magnetic and transport properties of the manganite perovskites [16][17][18]. Moreover, there are reports that suggest modification at the Mn site with Nb, Ni or Fe ions could promote change in the crystal phases, such as rhombohedral, orthorhombic or cubic phases, and influence the transition temperatures between these phases [19,20]. Furthermore, the magnetic properties of manganite perovskites are mainly determined by the magnetic ordering of Mn ions, hence, a modification at the Mn site with a slightly higher or lower oxidation state ion is expected to alter the short-and long-range magnetic interactions, leading to changes in the magnetic ordering temperature (T C ), magnetic transition width and the nature of the magnetic phase transitions [21].…”