Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Correlated Electrons: Spin Systems, Itinerant Magnets 3

TT 28.5: Vortrag

Dienstag, 12. März 2013, 10:30–10:45, H19

Heisenberg like critical properties, Magnetocaloric effect and Scaling in Lead doped NdMnO₃ Single Crystal — •Nilotpal Ghosh — School of Advanced Sciences, VIT University, Vellore-632014, Tamilnadu

Magnetic isotherms for single crystals of Nd_0.7Pb_0.3MnO₃ have been measured around the ferromagnetic(FM) to paramagnetic(PM) transition temperature T_C. Critical exponents have been obtained by modified Arrott plots and the Kouvel Fisher method. The values of exponents are consistent with those expected for 3D Heisenberg universality class. Magnetocaloric effect (MCE) has been also studied from the magnetic isotherms. Relative cooling power (RCP) is estimated as 56.725, 66.252 and 77.163 J/Kg for 1.2, 2.2 and 4.8 T fields respectively. Universal scaling behaviour in the relative change of magnetic entropy Δ S_M has been observed. The rescaled magnetic entropy change curves for different applied fields are noticed to collapse onto a single curve. It has been found that the peak entropy change, Δ S_M peak at T_C and RCP follow a scaling power law in magnetic field H with the exponents which are reduced in comparison to their theoretically estimated value.
[1] N. Ghosh, Journal of Superconductivity and Novel Magnetism, accepted (2012)
N. Ghosh, S. Roessler, U.K. Roessler, K. Nenkov, S. Elizabeth, H.L. Bhat, K. Doerr, and K.H. Mueller, J. Phys.: Condens. Matter 18, 557-567 (2006)