Ion-size effect on TN in (R1-xPrx)Ba2Cu3O7-y systems (R=Lu, Yb, Tm, Er, Y, Ho, Dy, Gd, Eu, Sm, and Nd) r.

We conducted a detailed study of the structure and magnetic properties of ([ital R][sub 1[minus][ital x]]Pr[sub [ital x]])Ba[sub 2]Cu[sub 3]O[sub 7] sintered samples, where [ital R]=Lu, Yb, Tm, Er, Y, Ho, Dy, Gd, Eu, Sm, and Nd for [ital x]=0.5--1.0. We found that the temperature dependence of the dc susceptibility follows the Curie-Weiss law in the temperature range 20--300 K and the paramagnetism of the Pr and [ital R] sublattices exist independently of one another. The antiferromagnetic ordering temperature [ital T][sub [ital N]] of Pr ions decreases monotonically with increasing [ital R] concentration (1[minus][ital x]). At a given [ital x], [ital T][sub [ital N]] is [ital R]-ion-size dependent. The slope in the [ital T][sub [ital N]] vs [ital x] curve is steeper for ions with smaller ionic radii. The observed results are interpreted in terms of the hybridization between the local states of the Pr ion and the valence-band states of the CuO[sub 2] planes.