Figure - available from: Applied Physics A
This content is subject to copyright. Terms and conditions apply.
Source publication
The magnetic behaviors and the magneto-caloric effect in a nano-structure formed on a hexagonal Dendrimer structure with the moment spin (S = 7/2) were studied. This examination allowed me, in fact, to observe that the ferromagnetic order appeared above the transition temperature (Tc) whose value was 305 K. Along with this parameter and with the ai...
Similar publications
Particle size as an effective tool for controlling the magnetic and magnetocaloric properties of Pr 0.6 Sr 0.4 MnO 3 samples has been studied. In the present work, a direct influence of particle size on the magnitude of magnetization and magnetic transition temperature, T C, can be seen. The T C drops from 309 to 242 K, while the saturation magneti...
Citations
Two macromolecular complexes derived from poly(propylene imine) with Co(II) and Ni(II) ions have been synthesized by direct complexation between metal salts and the second generation dendrimers. Based on experimental data one can assume the formation of a binuclear complex in the case of Co²⁺ while the Ni²⁺ complex is characterized by the filling of all possible coordination sites. Magnetocaloric behaviour of symmetric Co(II) and Ni(II) complexes was found. It has been established that when the synthesized samples are exposed to a magnetic field, the sign of the specific amount of heat (QMCE) changes. Analyzing the obtained data on the magnetocaloric effect of the complexes, it was shown that the MCE values are changed from the negative value ΔT (Co(II)) = -0.016 K, ΔT (Ni(II)) = -0.005 K to positive ΔT (Co(II)) = 0.011 K, ΔT (Ni(II)) = 0.002 K (at T = 337 K and 1 T). The presence of a maximum in the temperature dependences of the heat capacity indicates a second-order phase transition. It was found for the studied complexes that they exhibit enantiotropic mesomorphism with the formation of columnar phases.
The magnetic phase transition, magnetic and magnetocaloric effect of DyCo2‐xCrx (x=0.0‐0.2) compounds have been studied. XRD data show that the main phases of DyCo2‐xCrx compounds were MgCu2‐type cubic crystal structure, and the maximum atomic concentration of Cr in DyCo2 is 5%. With the × changed from 0.0 to 0.2, both of the lattice parameter and cell volume increased, and the coercivity at 10K increased from 890 Oe to 2839 Oe. With the introduction of Cr atoms, the type of magnetic phase transition can be regulated from the first‐order to the second‐order. Under a 5T magnetic field, the maximum magnetic entropy change (ΔSM) of DyCo2‐xCrx (x=0.0, 0.1 and 0.2) compounds are 10.4, 8.4 and 6.8 J/kg·K, respectively, but the relative cooling power (RCP) actually increased, with values of 290.6, 312.5 and 396.7 J/kg respectively, which is because the width at half‐maximum of the ΔSM peak (δTFWHM) is increased.
This article is protected by copyright. All rights reserved.
