The Pr0.5Ca0.5Mn1−xCrxO3 series (0 ≤ x ≤ 0.5):evidence of steps in the magnetic and transport properties for a narrowcomposition range

Abstract

The Pr0.5Ca0.5Mn1−xCrxO3 series has beeninvestigated up to x = 0.5. For lowdoping content (x ≤ 0.04),the introduction of Cr3+ favoursthe creation of ferromagnetic (FM) regions leading to phase-separation phenomena.Steps in the magnetic and transport properties measured versus field are observedand these properties strongly depend on the thermal history of the samples. Forx = 0.04–0.06,the samples are almost 100% FM. As the Cr3+concentration increases beyond this optimum doping level of 0.04–0.06, the FM fractionxFMslowly decreases, reflecting the fact that Cr3+is antiferromagnetically coupled to the Mn network, and reaches almost 0 forx = 0.5. Beyondthe optimum doping, the steps disappear. In a martensitic-like picture, the presence of stepsfor x < 0.04is consistent with the existence of phase separation. On theother hand, the disappearance of jumps beyond the optimumdoping shows that the nature of phase separation, if it exists forx > 0.04–0.06, is completelydifferent from the low-xside.