Magnetocaloric effect in manganites in alternating magnetic fields

Heat capacity, thermal conductivity and magnetocaloric effect in Heusler alloy Ni-=SUB=-47-=/SUB=-Mn-=SUB=-40-=/SUB=-Sn-=SUB=-13-=/SUB=-

“…It is known that values of adiabatic temperature change near second-order phase transitions must not depend on cyclic magnetic field frequency. Indeed, on the one hand, the recent studies of dependence T (T, f ) for Gd in the magnetic field of 1.2 T showed a frequency stability of MCE value in the interval of 1−20 Hz [30]. On the other hand, paper [31] notes a slight decrease of amplitude T ad for Gd with an increase of the magnetic field modulation amplitude from 116 to 1184 Hz in the field of 33 mT.…”

“…On the other hand, paper [31] notes a slight decrease of amplitude T ad for Gd with an increase of the magnetic field modulation amplitude from 116 to 1184 Hz in the field of 33 mT. The frequency studies of MCE in various magnetocaloric materials show a complex pattern of MCE dependence on cyclic field frequency, even for materials with second-order phase transitions [30][31][32][33]. While the dependence of T on magnetic field frequency near first-order phase transitions can be explained by growth and nucleation (phase transition kinetics), the situation is not so evident for second-order phase transitions.…”

Understanding the charge carriers dynamics in the La0.55Ca0.45Mn0.8Nb0.2O3 perovskite: scaling of electrical conductivity spectra

“…The optimal t for the oxygen content 3 − d was found to be d = 0.582 (3), where the experimental error of the renement is indicated between parentheses. Even so, the oxygen deciency extracted from the XPS analysis yields the value d = 0.727 (2). The difference between the XPS and XRD tting values is because the calculated from the XPS analysis corresponds to the combination of surface and bulk vacancy of oxygen, whereas the calculated from the XRD renement corresponds to the bulk vacancy.…”

“…Since the discovery of the colossal magnetoresistance property, the magnetocaloric effect, and related effects, perovskite-based ceramics have attracted excessive attention as active compounds in innovative alternatives to well-known technologies. [1][2][3] Therefore, perovskites show increasing attention thanks to their multifunctional applications that include the new generation spintronic eld, optoelectronics, information storage, solid oxide fuel cells (SOFCs), 4 and photovoltaic devices. 5 The most intensively investigated perovskite families are the manganite ceramics.…”