Abstract
The influence of magnetic field on the electrical properties of Tb1-xCaxMnO3 has been investigated by means of dielectric, polarization and neutron diffraction measurements. A field of 6 T applied along the b-axis induces a crossover from ferroelectric to relaxor behavior for the x = 0.02 compound at temperatures close to the ferroelectric transition. The mechanism of this field induced crossover involves a decrease in the coherence length of the Mn-spin-spiral structure due to increasing electron hopping rates associated with double exchange. Moreover, a large negative magnetocapacitance is observed at the freezing temperature for x = 0.05, which originates from suppression of the relaxor state and thus represents a new mechanism of magnetocapacitance.
AB - The influence of magnetic field on the electrical properties of Tb1-xCaxMnO3 has been investigated by means of dielectric, polarization and neutron diffraction measurements. A field of 6 T applied along the b-axis induces a crossover from ferroelectric to relaxor behavior for the x = 0.02 compound at temperatures close to the ferroelectric transition. The mechanism of this field induced crossover involves a decrease in the coherence length of the Mn-spin-spiral structure due to increasing electron hopping rates associated with double exchange. Moreover, a large negative magnetocapacitance is observed at the freezing temperature for x = 0.05, which originates from suppression of the relaxor state and thus represents a new mechanism of magnetocapacitance.
AB - The influence of magnetic field on the electrical properties of Tb1-xCaxMnO3 has been investigated by means of dielectric, polarization and neutron diffraction measurements. A field of 6 T applied along the b-axis induces a crossover from ferroelectric to relaxor behavior for the x = 0.02 compound at temperatures close to the ferroelectric transition. The mechanism of this field induced crossover involves a decrease in the coherence length of the Mn-spin-spiral structure due to increasing electron hopping rates associated with double exchange. Moreover, a large negative magnetocapacitance is observed at the freezing temperature for x = 0.05, which originates from suppression of the relaxor state and thus represents a new mechanism of magnetocapacitance.
| Original language | English |
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| Article number | 452203 |
| Number of pages | 7 |
| Journal | Journal of physics: Condensed matter |
| Volume | 21 |
| DOIs | |
| Publication status | Published - 11 Nov 2009 |