LAUSR

Si-based type-I clathrates with Ba-filler being partially replaced with Dy having the compositions Ba8–xDyxAlySi46–y have been synthesized. Their low temperature magnetic behavior together with high temperature thermoelectric properties have been investigated to understand charge and heat transport. Substitution of nonmagnetic Ba2+ with magnetic Dy3+ changes the magnetic behavior from diamagnetic to paramagnetic, which upon cooling transforms to an antiferromagnetic state at ∼12 K. The room temperature paramagnetic moment increases from 5.5 μB for x = 0.5 to 6.68 μB for x = 1.0 clearly showing the role of magnetic Dy3+. The antiferromagnetic state has been found to be unstable below 6 K and transforms to a ferromagnetic state. These transformations are reflected in the isothermal magnetic hysteresis, which also reveals the presence of metamagnetic transitions at 8 kG and 30 kG magnetic fields. The high temperature Seebeck coefficient shows an n-type behavior with a low value varying from ∼3 μVK–1 at 330 K...