The Magnetic Properties of the Series R₂V₂O₇ ; R= Lu, Yb, Tm

Abstract

<p>The magnetic behaviour of a series of pyrochlores R₂V₂O₇ (R= Lu, Yb, Tm) has been studied. They are all ferromagnetic below 70K, with the exchange interactions between vanadium atoms providing the driving force for the ordering. While the rare-earths, Yb(+3) and Tm(+3), remain paramagnetic down to 4K, an exchange field created by vanadium atoms causes the rare-earth and vanadium moments to align parallel. This positive exchange coupling is unusual. The low saturation magnetizations of Yb₂V₂O₇ and Tm₂V₂O₇ have been attributed to the effects, on the rare-earth ions, of the crystalline electric field.</p>