Influence of a first-order structural transition on magnetocaloric effects in manganese oxides

Influence of structural-phase transition on the magnetocaloric effects of lanthanum manganites

“…At the same time, there is a principal difference in effect of coupled and coincided structural transitions on the magnetic entropy change. Namely, in the former case, as in Gd 5 (Si 1Àx Ge x ) 4 , structural-phase transition and FM-PM transition are coupled, causing a giant value of MCE; whereas in the last (as in Ref [4]. and present study) those two phase transitions coincide.…”

“…The extremely high magnetocaloric effect found in Gd 5 (Si 1Àx Ge x ) 4 alloys [2] was associated with the sharp magnetization change under the magnetic-field-induced structural-phase transition [3]. At the same time, Terashita et al [4] observed the only little influence of structural transition, which was in close proximity to the ferromagnetic transition, on the magnetic entropy change (DS m ) in La 1Àx Sr x MnO 3 compositions.…”

Review of the magnetocaloric effect in manganite materials

“…The deviation of Eq. (6) occurring in the low temperature range is because the magnetic polarons are significantly depressed when the system is at a relative magnetic-ordered state [16,17]. In general, the relation (6) provides an alternative method to determine the magnetic entropy change in perovskite manganites from resistive measurements.…”

“…In manganites, both CMR (Colossal magnetoresistive) and MC (magnetocaloric) effects are often observed around the magnetic-ordering phase transition temperature (i.e., the Curie temperature) [11][12][13] and this evidently suggests that there exists a definite relation between magnetic entropy and resistivity [14][15][16][17]. In this case, Xiong et al [17] proposed a new method that allows evaluating the relation between the magnetic entropy and resistivity (r) of a manganite material by means of DS M ðT; HÞ ¼ Àa…”

Development of magnetocaloric materials in room temperature magnetic refrigeration application in recent six years

“…HOU et al [51] examined Some reports present that the crystal structure plays an important role in the transport, magnetic properties and thermodynamic properties of magnetic refrigerants. However, TERASHITA et al [53] observed the little influence of structural transition, which is in close proximity to the ferromagnetic transition, on ∆S M in La 1−x Sr x MnO 3 compositions. In order to elucidate the effect of lattice structure on the MCE, KIM et al [54] performed an experimental study on ∆S M in La 0.7 Ca 0.3−x Sr x MnO 3 (x=0.120, 0.135 and 0.150) ferromagnetics.…”