Magnetic Behavior of R2Ba2CuPtO8 Oxides (R=Ho, Er, Tm, Yb, Lu, and Y)

• Published in: Journal of solid state chemistry Vol. 165; no. 2; pp. 297 - 302
• Main Authors: Romero de Paz, J., Sáez Puche, R., Martı́nez, J.L., Baran, E.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-05-2002; Elsevier
• Subjects: antiferromagnetism; Condensed matter: electronic structure, electrical, magnetic, and optical properties; copper–lanthanide oxides; Exact sciences and technology; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; metamagnetism; Physics; superexchange interactions; metamagnetism; superexchange interactions; antiferromagnetism; copper–lanthanide oxides; Antiferromagnetism; Platinum oxides; Inorganic compounds; Curie point; Magnetization; Magnetic ordering; Rare earths Oxides; Transition element compounds; Curie-Weiss law; Rare earth compounds; Experimental study; Magnetic transitions; Magnetic susceptibility; Metamagnetism; Multi-element compounds; Barium oxides; Superexchange interactions; Sublattices; Neel temperature; Copper oxides; Yttrium oxides
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.2002.9533

Magnetic properties of polycrystalline R2Ba2CuPtO8 (R=Ho, Er, Tm, Yb, Lu and Y) oxides have been studied from magnetization and magnetic susceptibility measurements. The lutetium and yttrium oxides behave as antiferromagnets and the estimated Néel temperatures are 5.2 and 5.7 K, respectively. In the case of the remaining R2Ba2CuPtO8 oxides, Cu2+ and R3+ become antiferromagnetically ordered simultaneously, with the exception of TmBa2CuPtO8, where the χ vs T plot exhibits two maxima at 8 and 5 K, which have been assigned to the Néel temperatures of Cu2+ and Tm3+ sublattices, respectively. Taking into account the structure, a superexchange mechanism of the type R–O–Cu–O–R has been proposed in which the Cu2+ sublattice plays an important role as promoter of the antiferromagnetic interactions of ferromagnetically R3+ coupled in the a–c plane of the structure. Field-induced metamagnetic transitions have been observed below the Néel temperature in all cases; however, different critical fields are achieved depending on the nature of R3+ ions.