{'fraction_non_alphanumeric': 0.040280210157618214, 'fraction_numerical': 0.0297723292469352, 'mean_word_length': 5.145161290322581, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Preparation and properties of epitaxial La0.7Ca0.3MnO3-δ films with reduced carrier density

Epitaxial La0.7Ca0.3MnO3-δ thin films have been grown on LaAlO3(100) substrates by magnetron sputtering. By vacuum annealing at temperatures below 600 °C, oxygen-deficient films with ferromagnetic ordering temperatures, TC, between 130 K and 270 K have been prepared. Oxygen deficiency reduces the Mn4+ content, i.e. the charge carrier density of the films. Effective oxygen diffusion was observed at temperatures as low as T = 80 °C. Resistance, magnetization and magnetoresistance behaviours of the films are reported. Our results are consistent with a magnetically phase-separated ground state - a mixture of ferromagnetic metallic and antiferromagnetic insulating regions - of La0.7Ca0.3MnO3-δ for an Mn4+ concentration below ~20%. The electrical transport in the oxygen-deficient films, e.g. the non-monotonic temperature dependence of the resistance, the large magnetoresistance at T<TC and the low-field magnetoresistance observed for some of the investigated samples, can be explained by a percolation mechanism in the phase-separated state.