S.K. Barik
National University of Singapore
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Featured researches published by S.K. Barik.
Applied Physics Letters | 2011
V. B. Naik; S.K. Barik; R. Mahendiran; B. Raveau
We investigated magnetic entropy change (ΔSm) in the A-type antiferromagnet Pr0.46Sr0.54MnO3 by magnetic and differential scanning calorimetry (DSC) methods. The field-induced antiferromagnetic to ferromagnetic transition is first-order in nature and is accompanied by a large change in the latent heat as evidenced by the DSC data. The ΔSm shows an inverse magnetocaloric effect (ΔSm=+9 J kg−1 K−1 for ΔH=7 T) around the Neel temperature (TN=210±2 K) by magnetic measurement, which closely agrees with the calorimetric results. It is suggested that the large positive ΔSm results from a field-induced structural transition that accompanies the destruction of antiferromagnetism.
Journal of Applied Physics | 2010
S.K. Barik; R. Mahendiran
We investigated the effect of Bi doping on magnetic and magnetocaloric properties of La0.7−xBixSr0.3MnO3 (x=0.0–0.4). It is shown that the low temperature ground state changes from a ferromagnet (x=0) to a charge-ordered antiferromagnet for x=0.4. While the paramagnetic-ferromagnetic (PM-FM) transition is second-order in x≤0.25, it changes into first-order for x=0.3 which is at the magnetic phase boundary. The changes in the magnetic ground state affect magnetic entropy. The magnitude of the isothermal magnetic entropy (|ΔSM|) at the FM Curie temperature increases from 4.56 J/kg K for x=0 to a maximum value of 5.02 J/kg K for x=0.05 and then decreases to nearly zero for x=0.4 at the charge order transition. In contrast to x≤0.25, the ΔSM of x=0.3 is magnetic history dependent and its temperature dependence exhibits a clear step at TCO=260 K followed by a plateau between 240 and 185 K. Although |ΔSM|=3.1 J/kg K of x=0.3 is small compared to other compositions, it has a high relative cooling power (325 J/kg...
Journal of Applied Physics | 2011
S.K. Barik; R. Mahendiran
We report the magnetic field and temperature dependences of ac electrical transport in La0.5Ca0.5 Mn0.96Ni0.04O3 as a function of frequency. The ac magnetoresistance shows an anomalous behavior as a function of field: it is negative and exhibits a bell shaped curve about the origin (H = 0 T) at f = 0.1 MHz, but it transforms into a valley at the origin (accompanied by a positive peak on either side of the origin) for f ≥ 3 MHz at T = 125 K. With increasing frequency, the depth of the valley increases and the position of the peak shifts toward higher field. However, the magnetoreactance is negative and exhibits only a single peak at the origin for all temperatures and frequencies. At T = 125 K and f = 5 MHz, a magnetoresistance of +80% and a magnetoreactance of −90% were found for H = 2 T. These results are very different from those for La0.7Sr0.3MnO3, and we discuss the possible origins of the observed anomalous ac magnetotransport in this compound.
Journal of Magnetism and Magnetic Materials | 2011
S.K. Barik; C. Krishnamoorthi; R. Mahendiran
Solid State Communications | 2010
C. Krishnamoorthi; S.K. Barik; Z. Siu; R. Mahendiran
Solid State Communications | 2011
C. Krishnamoorthi; S.K. Barik; R. Mahendiran
Journal of Physics D | 2008
S.K. Barik; A. Rebello; Celine Tan; R. Mahendiran
Journal of Magnetism and Magnetic Materials | 2012
M. Aparnadevi; S.K. Barik; R. Mahendiran
Solid State Communications | 2011
S.K. Barik; R. Mahendiran
Solid State Communications | 2011
C. Krishnamoorthi; S.K. Barik; R. Mahendiran