Stabilization of antiferromagnetic phase under hydrostatic pressure in layered perovskite cobaltites Nd1-xCaxBaCo2O5.5 (x = 0–0.06)

• Published in: Journal of applied physics 2014-07, Vol.116 (1)
• Main Authors: Pietosa, J, Szewczyk, A, Puzniak, R, Wisniewski, A, Dabrowski, B, Kolesnik, S
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Applied physics; Dependence; Doping; Ferrimagnetism; Hydrostatic pressure; Induced polarization; Magnetic fields; Magnetic measurement; Magnetic moments; Magnetism; Neodymium; Perovskites; Phase transitions; Temperature
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4885881

Magnetic measurements have been performed under pressure of 0–9.7 kbar and in the temperature range of 5–300 K for the hole-doped Nd1-xCaxBaCo2O5.5 system over the composition range x = 0–0.06, where a strong competition between antiferromagnetic and ferrimagnetic phases is present. The dependence of TN, i.e., of the temperature of a first order phase transition from the antiferromagnetic to the ferrimagnetic state, and of TC, i.e., of the temperature of the second order phase transition from the ferrimagnetic to the paramagnetic state on hydrostatic pressure was found to be a function of hole doping. The large pressure-induced increase of TN becomes enhanced with increasing of the hole doping level, while a small pressure-induced increase of TC is suppressed by increasing the hole doping level. This finding shows that the hydrostatic pressure stabilizes the antiferromagnetic phase, whereas the hole doping alone suppresses the antiferromagnetic phase. All investigated compounds have revealed the existence of a certain fraction of ferrimagnetic phase at temperatures much below TN. An increase of a magnetization observed in high magnetic field of 50 kOe at temperatures much below TN was explained as the high-field induced polarization of Nd3+ magnetic moments, appearing in the magnetic field exceeding the strength of Nd-Co antiferromagnetic exchange interactions.