Electrical and thermal properties of Pr0.6Sr0.4−xAgxMnO3 (x = 0.05 and 0.1) manganite

Abstract

Monovalent silver-doped Pr0.6Sr0.4−xAgxMnO3 manganite has been chosen for the electrical and thermal transport studies. The electrical measurements confirmed a metal–insulator transition around room temperature. For the analysis of the resistivity data, in the high-temperature paramagnetic region, the adiabatic small polaron hopping model was operative. The magnetoresistance studies, under different external magnetic field, showed that the MR peak is located at the metal–insulator transition and ferromagnetic–paramagnetic transition, which is characteristic for an intrinsic magnetoresistance. The thermal conductivity results exhibit a semicrystalline character with grain boundary scattering as a main mechanism limiting the heat transfer in samples. The electrical contribution to the thermal conductivity is relatively small, around 1%, as in most of the manganites. The transition point around room temperature is also visible. The additionally calculated thermal diffusivity parameter shows values of the order typically found in perovskites.

Charge-ordering breakdown dynamics and ferromagnetic resonance studies of B-site Cu diluted Pr1‒x Sr x MnO3

“…Since both phonon and magnetic contributions are present at T < T C , the above equation is not expected to fit to the data of figure 6 for T < 220.5 K. The C P (0 Oe) curve is fitted to the above equation for T ≫ T C and derived C ph , where it is anticipated that C mag have almost nil contribution. This analysis yields the value Θ D to be 743 K for this pristine system which is slightly greater than the Debye temperature reported for the Pr 0.6 Sr 0.35 Ag 0.05 MnO 3 and Pr 0.6 Sr 0.3 Ag 0.1 MnO 3 systems [51]. Detailed specific heat data across the transition temperatures for heating and cooling cycles have been shown in figures 7 and 8 which reveals that S55 shows a thermal hysteresis of 2.56 K (4.3 K) across T CO at H=0 Oe (90 kOe).…”

Giant magnetoresistance resulting from superzone gap in spin-frustrated rare-earth-based aluminide: DyFe2Al10

“…Increasing the magnetic field diminishes the e − e interaction. This observation can be attributed to the overall reduction of spin fluctuations in the presence of an external magnetic field [48]. An important point to note is that the contribution from the T 2 dependence is two orders of magnitude smaller compared to the linear T dependence.…”

“…From around 60 K to T N , a gradual decrement in MR is observed. Typically, when a system undergoes a paramagnetic to ferromagnetic transition, its MR decreases due to the decrement of spin fluctuation in presence of magnetic field [48]. Therefore, we can attribute MR below T N to be governed by the superzone gap, and above T N , it is mainly governed by short-range ferromagnetic ordering.…”

Polycrystalline La0.66Gd0.04Ca0.3MnO3 for magnetic-response applications: concurrent anisotropic magnetoresistance and magneto-transport under a low magnetic field

“…The overall reduction of the spin fluctuations under an external magnetic field contributed significantly to this phenomenon. 51 More specifically, the r 2 Â 10 À10 value of Gd004 under a 1 T parallel magnetic field (2010.4 O cm K À1 ) is about 6 times smaller than that in the absence of the field (10544.6 O cm K À1 ) and under a 1 T vertical magnetic field (12 555.0 O cm K À1 ), which exhibits the greatest variability in the series. The ordering of the carrier local spin along the z-axis in the octahedron could be strongly promoted by the parallel magnetic field, and a significantly lower probability of the interelectron scattering was observed in the transport process.…”