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    Öğe
    Effects of Ca substitution on magnetic and magnetocaloric properties in PrBa1-xCaxMn2O6 system
    (Academic Press Inc Elsevier Science, 2023) Kandemir, Arda; Akca, Gonul; Cetin, Selda Kılıç; Ayas, Ali Osman; Akyol, Mustafa; Ekicibil, Ahmet
    In this study, we have examined the effect of Ba substitution by Ca on the magnetic, and magnetocaloric properties of PrBa1-xCaxMn2O6 (x = 0, 0.2 and 0.3) double perovskite manganites produced using sol-gel method. The samples were indexed in orthorhombic structure (with space group of Pbnm). The temperature-dependent magnetization, M(T), measurements indicate that all samples have a magnetic phase transition from ferromagnetic (FM) to paramagnetic (PM) state with increasing temperature. Curie temperature (T-C) decreases with increasing Ca content in the main lattice. From the magnetic field dependence of magnetization measurements, M(H), maximum magnetic entropy change (-Delta S-M(max)) values were calculated as 4.07, 4.12, and 5.04 Jkg(-1)K(-1) under 5 T for PrBaCaMn2O6, PrBa0.8Ca0.2Mn2O6, and PrBa0.7Ca0.3Mn2O6 samples, respectively. Relative cooling power (RCP) values below 5 T were determined as 214.16, 227.14 and 279.62 Jkg(-1) based on the increasing Ca content. The -Delta S-M(max) and RCP values enhance with increasing Ca content, respectively. The nature of the phase transition, checked by Banerjee criterion and Franco's universal master curves, was found to be second order magnetic phase transition (SOMT).
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    Öğe
    Investigation of the effect of sintering temperature on structural, magnetic and magnetocaloric properties in PrCaMn2O6 double perovskite manganite system
    (Springer, 2022) Ayas, Ali Osman; Kandemir, Arda; Cetin, Selda Kılıç; Akca, Gonul; Akyol, Mustafa; Ekicibil, Ahmet
    We have studied the effect of sintering temperature change on structural, magnetic and magnetocaloric properties of PrCaMn2O6 compound. The samples were produced by using solid-state-reaction process and then sintered at 1000, 1100 and 1200 degrees C temperatures. The Rietveld refinement results indicate that the crystal symmetry of the produced samples is tetragonal with P4mm space group. All samples include impurity phase, and their percentages decrease with increasing sintering temperature. Scanning electron Microscope images show that grain sizes of samples increase with increasing T-S. Energy-dispersive X-ray spectra indicate that samples include all required starting elements. Temperature-dependent magnetization measurements show that samples have the Curie temperatures as 42.6, 43.1, and 42.8 K for samples sintered at 1000, 1100 and 1200 degrees C, respectively. Magnetic entropy change values are found as 1.19, 1.59 and 1.72 J kg(-1) K-1 at 5 T magnetic field change for samples sintered at 1000, 1100 and 1200 degrees C, respectively. Relative cooling power values are calculated as 14.28, 20.54 and 17.20 J kg(-1) for samples sintered at 1000, 1100 and 1200 degrees C, respectively. The universal curve and the Arrott plots show that magnetic phase transition type of all samples is second order.
  • [ X ]
    Öğe
    Magnetocaloric effect in PrGd1-xBaxMn2O6 (0.0 ? x ? 1.0) double perovskite manganite system
    (Springer, 2023) Akca, Gonul; Kandemir, Arda; Ayas, Ali Osman; Kılıç Cetin, Selda; Akyol, Mustafa; Ekicibil, Ahmet
    The PrGd1-xBaxMn2O6 (x = 0.0, 0.6, 0.7, 0.8, 0.9, 1.0) double-perovskite manganite samples produced by solid-state reaction method have been investigated in this study. The samples were crystallized in the form of orthorhombic structure with the Pbnm space group confirmed by the Rietveld refinement method. The temperature-dependent magnetization measurements (M(T)) revealed that the samples display a phase transition from ferromagnetic to paramagnetic as temperature increased. The results obtained from these measurements indicate that the Curie temperature values increased from 44 to 187.8 K, respectively, by increasing the Ba concentration from x = 0.0-1.0. The isothermal magnetization curves are achieved by external magnetic field-dependent magnetization measurements (M(H)) and help to calculate the magnetic entropy change (- Delta S-M) values, and to find the nature of magnetic phase transition. Maximum magnetic entropy change (Delta S-M(max)) values are found as 2.81, 2.76, 2.99, 3.44, 2.77, and 2.14 Jkg(-1) K-1 under 5 T magnetic field change for x = 0.0, 0.6, 0.7, 0.8, 0.9, 1.0 samples, respectively. Arrott plots created from the isothermal magnetization curves show that all samples have a second-order magnetic phase transition. Relative cooling power values are determined as 103.41, 264.96, 341.19, 278.36, 224.13, and 164.42 Jkg(-1) for x = 0.0, 0.6, 0.7, 0.8, 0.9, 1.0 samples, respectively.