Magneto- and electro-resistance effects in phase separated Pr0.55(Ca0.65S0.35)0.45MnO3 films

Abstract

Pr0.55(Ca0.65S0.35)0.45MnO3 films were deposited on (001) (La0.18Sr0.82)(Al0.59Ta0.41)O3 substrates using pulse laser deposition technique and annealed in oxygen environment at temperatures ranging from 900 to 1100 °C, respectively. X-ray diffraction data suggested that these epitaxial films show a little relaxation in lattice strain without structural change after post-annealing within this temperature range. The as-deposited film and the film annealed at 900 °C showed only insulating and weak magnetic behaviors, but the film annealed at 950 °C depicted a clear metal-insulator (M-I) transition with a strong ferromagnetic property while increased annealing temperature lead to a slight degradation in both electric and magnetic properties. Interestingly, the slightly degraded films above 950 °C showed larger magnetoresistance and electroresistance than the optimized film at 950 °C. The temperature dependence of resistance for the film annealed at 1000 °C was measured at various magnitudes of dc current, and its peak resistance was found to decrease exponentially with increasing current. From a comparison between magnetoresistance and electroresistance, we found that the resistance was suppressed equally by either the application of a 0.7 T magnetic field or a 6 mA current.

Magnetoresistance and electroresistance effects in Fe3O4nanoparticle system

“…This excitation current-dependent resistance state of the Fe 3 O 4 material can be attributed to the influence of electric field on the intrinsic charge ordered state. The upward and downward temperature scans (indicated by forward and backward arrows in Figure 4) with 10 mA excitation current does not show any thermal hysteresis that is expected in case the local joule heating effect is prominent [29]. In addition, we do not see any abnormal changes in the sample temperature that are indicative of joule heating, even though in our experimental setup the temperature sensor is separated only by a thin sapphire plate from the sample.…”

Effect of substrate and orientation on charge ordering behaviors in epitaxial Pr0.5Ca0.35Sr0.15MnO3 films

“…It has a narrow e g band and its physical properties vary greatly as the x or y changes. [17][18][19][20][21][22] Tomioka and Tokura 23 obtained the phase diagram and lattice parameters of Pr 1-x (Ca 1-y Sr y ) x MnO 3 with different x and y, which may convert from CO state to ferromagnetic metal (FM) state. From the phase diagram it is demonstrated that the bulk Pr 0.5 Ca 0.35 Sr 0.15 MnO 3 (PCSMO) is in CO state at low temperature and the T CO is about 190 K. Zhao et al 24 studied the effect of the substrate on the CO phase and transport behaviors, and showed that a large magnetic field is needed to melt CO phase if the film suffers tensile strain, indicating that tensile strain could enhance the stability of CO phase.…”