Magnetocaloric effect and critical behavior in La0.8K0.2MnO3 nanoparticle

• We report on the magnetocaloric effect and critical phenomenon on La0.8K0.2MnO3 nanoparticle through a systematic magnetic and electrical measurement. The magnetic entropy change (Delta S-M) presents close values obtained from resistivity and magnetic measurements, however, with a discrepancy in the magnetic entropy maximum values. This discrepancy is due to the presence of an extrinsic effect associated with the nanometric grain size affecting the electrical behavior. Interestingly, our results show a good agreement with the calculation of the critical exponents and the temperature coefficient of resistance shows positive and negative values. The obtained critical exponents are close to that of the mean-field theory (with beta = 0.5, gamma = 1, and delta = 3). This indicates a long-range interaction between spins a consequence of the presence the presence of dipole- dipole interaction in this system.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Electric

Magnetic

Magnetocaloric effect

Critical behavior

Temperature coefficient of resistance

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