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Collapse of the charge ordering state at high magnetic fields in the rare-earth manganite, Pr_{0.63}Ca_{0.37}MnO_3

K. S. Nagapriya·A. K. Raychaudhuri·Bhavtosh Bansal·V. Venkataraman·Sachin Parashar·C. N. R. Rao
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Abstract

We have investigated the specific heat and resistivity of a single crystal of Pr_{0.63}Ca_{0.37}MnO_3 around the charge ordering (CO) transition temperature, T_{CO}, in the presence of high magnetic fields (<=12T) which can melt the charge ordered state. At low magnetic fields (<=10T), the manganite transforms from a charge-disordered paramagnetic insulating (PI) state to a charge-ordered insulating (COI) state as the temperature is lowered. The COI state becomes unstable beyond a threshold magnetic field and melts to a ferromagnetic metallic phase (FMM). This occurs for T < T_{CO}. However, above a critical field μ_0H_ρ^*, the sample shows the onset of a metallic phase for T>T_{CO} and the COI transition occurs from a metallic phase. The onset temperature of the high-field metallic behavior decreases with an increase in the field and above a field μ_0H^*, the COI transition does not occur and the CO state ceases to occur at all T. The entropy change involved in the CO transition, ΔS_{CO}~1.6J/molK at 0T, decreases with increasing field and eventually vanishes for a field μ_0H^*. The collapse of the CO state above μ_0$H$^* is thus associated with a collapse of the entropy that stabilizes the CO state.

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K. S. Nagapriya, A. K. Raychaudhuri, Bhavtosh Bansal, V. Venkataraman, Sachin Parashar, C. N. R. Rao. 2006-02-10. Collapse of the charge ordering state at high magnetic fields in the rare-earth manganite, Pr_{0.63}Ca_{0.37}MnO_3. https://doi.org/10.1103/physrevb.71.024426

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