Pressure and magnetic field effects on Pr1-x Cax MnO3 thin films

• Published in: Physica Status Solidi (b) Vol. 246; no. 3; pp. 622 - 625
• Main Authors: Antonakos, A., Filippi, M., Auban-Senzier, P., Lampakis, D., Pasquier, C. R., Prellier, W., Liarokapis, E.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01-03-2009; WILEY‐VCH Verlag
• Subjects: 61.05.cp; 74.62.Fj; 75.47.Lx; 78.30.−j
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200880539

We report a systematic study of Pr1–x Cax MnO3 (x = 0.4 and 0.6) thin films grown on LaAlO3 (LAO) substrate (PCMO/LAO). X‐ray diffraction measurements have shown that the PCMO/LAO film is [101]‐oriented and under compressive strain due to the lattice mismatch. According to Raman spectroscopy the Jahn–Teller modes are suppressed under the application of pressure in the PCMO (x = 0.4) thin film. In particular, it was found that a pressure of 2 GPa suppresses the charge ordered state. Further high pressure measurements have confirmed that resistivity decreases linearly up to 2.4 GPa corresponding to a total reduction of about 35% in resistivity leading to a more conductive state on both concentrations. The temperature dependence of the resistivity has shown that the samples under pressure retain their semiconducting behavior. At ambient pressure the PCMO (x = 0.6) film shows a moderate magnetoresistance in the range 0–7 T and no metal to insulator transition (MIT). Raman spectroscopy confirmed that the application of a magnetic field of 1 T does not induce any remarkable changes on the electron–phonon interaction. Although, the hydrostatic pressure is not enough to induce a macroscopic metallic state, its effect is much greater than the one of the magnetic field. In addition, the effect of the 7 T magnetic field appears the same at ambient pressure and 2.5 GPa. Therefore the two effects of hydrostatic pressure and magnetic field do not seem to be coupled, at least up to the magnitudes studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)