Abstract :
We have synthesized three Y bMn6Sn6−xInx representatives ( x = 0.45 , 0.80, 1.20), the first pseudo-ternary RMn6Sn6−xX′x compounds involving a divalent R metal. The crystal structure is found to evolve with the In concentration without modification of the Yb valency: Y bMn6Sn5.55In0.45 is isotypic with HoFe6Sn6 ( I m m m ) while Y bMn6Sn5.20In0.80 and Y bMn6Sn4.80In1.20 crystallize in the TbFe6Sn6-type ( C m c m ). The In content is also determining as regards the magnetic and magnetocaloric properties: Y bMn6Sn5.55In0.45 ( T C = 216 K ) almost behaves like a simple ferromagnet while Y bMn6Sn5.20In0.80 and Y bMn6Sn4.80In1.20 also order ferromagnetically but at significantly lower temperatures ( T C = 154 K and 129 K, respectively) and are further characterized by the interference of low temperature antiferromagnetic interactions. The results are discussed and compared to previously published data.
