Magnetic and magnetocaloric properties of Pr1−xSrxCoO3 cobaltites

Magnetic and magnetocaloric properties of La0.55Bi0.05Sr0.4CoO3 and their implementation in critical behaviour study and spontaneous magnetization estimation

“…Physical effects such as magnetoresistance and magnetocaloric effects observed in manganites 10,11 and cobaltites 3,12–14 have been the subject of several investigations in the last few years. Double exchange (DE), phase separation (PS), Jahn–Teller distortion (JT), and Griffiths phase (GP) have been found to explain the aforementioned effects.…”

Spin state and magnetic ordering of half-doped Nd0.5Sr0.5CoO3 cobaltite

“…Perovskite cobaltites exhibit general formula of type Ln 1−x A x CoO 3 (Ln: lanthanides, A: alkaline-earth metals) and are very interesting materials due to the their remarkable magnetic and electrical properties, that lead to eects such as the giant magneoresistance [1], giant anisotropic magnetostricition [2], huge values of Hall coecient [3] and magnetocaloric eect [4,5], just to name a few. The interest on these materials has been revived in recent years due to the possibility of applications on solid oxide fuel cells [6], chemical reactors, gas separation membranes [7] and other applications [8].…”

“…Physical properties of cobaltites, as well as manganites, depends on the interplay between charge, spin, orbital and lattices degrees of freedom; however, cobaltites have an additional degree of freedom as Co 3+ and Co 4+ can occur in three dierent spin congurations [9]: low-spin LS (t 6 2g e 0 g for Co 3+ and t 5 2g e 0 g for Co 4+ ), intermediate-spin IS (t 5 2g e 1 g for Co 3+ and t 4 2g e 1 g for Co 4+ ) and high-spin HS (t 4 2g e 2 g for Co 3+ and t 3 2g e 2 g for Co 4+ ). This unusual exibility arises from the comparable energies between the Hund's coupling and the crystal-eld splitting [9].…”

“…The Curie temperature, for this heavy doped region of the phase diagram, decreases with decreasing the size of the rareearth ion. La 1−x Sr x CoO 3 [8,1,2] and Pr 1−x Sr x CoO 3 [11,12,4] series are the most studied cobaltites, and the latter are more interesting due to the nonzero magnetic moment of Pr. Some compounds of Pr 1−x Sr x MnO 3 series, for example, exhibit a broad peak in the susceptibility data around 90 K, whose origin is a open question on the literature [4]; with some authors claiming that it is due to a state spin transition from the intermediate to low-spin state [13], while other researchers argue that it is only a changing on the ferromagnetic state associated with orbital ordering [11].…”

Facile synthesis and conduction mechanism in RE-substituted oxide systems for enhanced thermoelectric performance

“…Rare earth element doping was earlier favored by Tang et al [5] according to which spin-entropy enhanced due to rare earth element doping at Ca-site resulting in enhanced thermopower described on the basis of modified Heikes formula [6]. Many efforts in improving thermoelectric properties of cobaltites were made with the help of doping, some of them are [7][8][9]. Although Ca-site is preferred for substitution as it disturbs only concentration of charge carriers and does not affects the overall band structure and transport mechanism which is the case in Co-site substitution [10].…”