相关论文: Inverse magnetocaloric effect in polycrystalline L…
Some recent experimental studies show the invisibility of antiferromagnetic transition in the cases of manganites when their particle size is reduced to nanometer scale. In complete contrast to these cases, we have observed the signature of…
$La_{0.7}Ca_{0.3}MnO_3$ samples were prepared in nano- and polycrystalline forms by sol-gel and solid state reaction methods, respectively, and structurally characterized by synchrotron X-ray diffraction. The magnetic properties determined…
The magnetocaloric effect in alternating magnetic fields has been investigated in Pr1-xAgxMnO3 manganites with x=0.05-0.25. The stepwise reversal of the sign of the magnetocaloric effect has been revealed in a weakly doped sample (x=0.05)…
The magnetocaloric effect (MCE) in the A-site ordered manganite NdBaMn2O6 is studied. The MCE in this compound has an anomalous behavior. In low magnetic fields, the abrupt transitions between direct and inverse magnetocaloric effect are…
We report magnetic and magnetocaloric properties of Sm0.6-xLaxSr0.4MnO3 (x = 0-0.6). A rapid increase around TC and an anomalous peak at a temperature T*<<TC occur in magnetization which lead to normal and inverse magnetocaloric effects…
The magnetocaloric effect (MCE) of A-site ordered PrBaMn2O6 manganite has been studied by direct methods and by the specific heat measurements. Direct measurements of the MCE in low magnetic fields were performed using recently proposed…
We present a study of the magnetocaloric effect in La5/8-yPryCa3/8MnO3 (y=0.3) and Pr0.5Ca0.09Sr0.41MnO3 manganites. The low temperature state of both ystems is the result of a competition between the antiferromagnetic and ferromagnetic…
The magnetocaloric effect (MCE) in paramagnetic materials has been widely used for attaining very low temperatures by applying a magnetic field isothermally and removing it adiabatically. The effect can be exploited also for room…
The magnetocaloric effect in exchange-coupled synthetic-antiferromagnet multilayers is investigated experimentally and theoretically. We observe a temperature-controlled inversion of the effect, where the entropy increases on switching the…
Large thermal changes driven by a magnetic field have been proposed for environmentally friendly energy efficient refrigeration, but only a few materials which suffer hysteresis show these giant magnetocaloric effects. Here we create giant…
A technology of obtaining the single-phase ceramic samples of La1-xKxMnO3 manganites and the dependence of their structural parameters on the content of potassium has been described. Magnetocaloric effect (MCE) in the obtained samples has…
Polycrystalline Heusler compounds Ni2Mn0.75Cu0.25Ga0.84Al0.16 with a martensitic transition between ferromagnetic phases and Ni2Mn0.70Cu0.30Ga0.84Al0.16 with a magnetostructural transformation were investigated by magnetization and thermal…
In this paper, we report on the magnetocaloric properties of some selected multiferroic oxides, namely HoMn2O5 and La2(Ni,Co)MnO6 compounds which exhibit transition points from 10K up to almost room temperature. In order to avoid grain…
Manganites have been attracted considerable attention due to some intriguing magnetic properties, such as magnetoresistance, spin glass behavior and superparamagnetism. In recent years, some studies point to the effect of particle size and…
It is shown that the use of sandwich from materials with near similar magnetocaloric properties increases the relative cooling power by about 20 %.
Applying a magnetic field to a ferromagnetic Ni$_{50}$Mn$_{34}$In$_{16}$ alloy in the martensitic state induces a structural phase transition to the austenitic state. This is accompanied by a strain which recovers on removing the magnetic…
The isothermal entropy change and the adiabatic temperature change for the exactly solved spin-1/2 Fisher's super-exchange antiferromagnet are rigorously calculated in order to examine magnetocaloric properties of the model in a vicinity of…
The existence and feasibility of the multicaloric, polycrystalline material 0.8Pb(Fe1/2Nb1/2)O3-0.2Pb(Mg1/2W1/2)O3, exhibiting magnetocaloric and electrocaloric properties, are demonstrated. Both the electrocaloric and magnetocaloric…
The crystal and magnetic structure of polycrystalline $La{}_{0.5-x}Nd{}_{x}Ca_{0.5}MnO{}_{3}$ (0.0 \ensuremath{\le} x \ensuremath{\le} 0.5) samples have been investigated using magnetization, resistivity, transmission electron microscope,…
In the present work we analyze the influence of the charge-ordering on the magnetocaloric effect of Pr$_{1-x}$Ca$_x$MnO$_3$ manganites. The results for the samples with $x<$0.30 present the usual ferromagnetic behavior, peaking at the Curie…