Field-induced phase transition, weak ferromagnetism, and metamagnetic transition in the underdoped PrBCO cuprate

Abstract In the present paper we report on the magnetic properties of nonsuperconducting PrBa 2 Cu 3 O 6.44 (PrBCO 6.44 ) ceramic sample under high DC magnetic fields up to 11 and 16 T, respectively in the range of temperatures 1.35-20 and 2-12 K. By analyzing the T -dependence of magnetization and its derivatives, we reveal significant field-induced effects. Anomalies are observed at the low-critical point ( T cr = 4-5 K), spin reorientation phase transition temperature ( T 2 = 6.5 K), and Néel temperature ( T N (Pr) = 9 K) of the Pr antiferromagnetic order. Arrott plot analysis identifies field-induced phase transitions at critical fields H cr1  3.3 T and H cr2 ~ 7.5 T. Among novel findings, we observe a weak ferromagnetic-like behavior that persists well above T N (Pr). By employing a sensitive vibrating sample magnetometer 2 T, we detect weak field-induced metamagnetic phase transitions at threshold fields H t below 0.16 T from 100.7 K down to 4 K and this, after crossing T N (Pr). Our results shed light on the weak ferromagnetism coexisting with predominated antiferromagnetism in both Pr and Cu(2) subsystems, and provide insights into the complex Pr-Cu(2) interactions in this underdoped PrBCO cuprate.