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

✍ Scribed by J. Romero de Paz; R. Sáez Puche; J.L. Martı́nez; E. Baran

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 245 KB
• Volume: 165
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9533

✦ Synopsis

Magnetic properties of polycrystalline R 2 Ba 2 CuPtO 8 (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 NeH el temperatures are 5.2 and 5.7 K, respectively. In the case of the remaining R 2 Ba 2 CuPtO 8 oxides, Cu 2؉ and R 3؉ become antiferromagnetically ordered simultaneously, with the exception of TmBa 2 CuPtO 8 , where the vs T plot exhibits two maxima at 8 and 5 K, which have been assigned to the NeH el temperatures of Cu 2؉ and Tm 3؉ sublattices, respectively. Taking into account the structure, a superexchange mechanism of the type R+O+Cu+O+R has been proposed in which the Cu 2؉ sublattice plays an important role as promoter of the antiferromagnetic interactions of ferromagnetically R 3؉ coupled in the a+c plane of the structure. Field-induced metamagnetic transitions have been observed below the NeH el temperature in all cases; however, di4erent critical 5elds are achieved depending on the nature of R 3؉ ions. 2002 Elsevier Science (USA)