Magnetic transitions and magnetoresistance of -type () compounds

Magnetic transitions and magnetotransport properties of polycrystalline Tb1−xGdxMn6Ge6 ( x = 0.2 – 1.0 ) compounds have been investigated by magnetic property and resistivity measurements in an applied magnetic field up to 50 kOe. The cell parameter a , c and cell volume V of compounds ( x = 0.2 – 1.0 ) increase with an increasing Gd content. The compounds ( x = 0.2 – 1.0 ) show a rich variety of magnetic behavior, such as antiferromagnetic, ferrimagnetic and paramagnetic state with increasing temperature. Their Curie temperatures increase almost linearly with an increasing Gd content from 460 K for x = 0.2 to 484 K for x = 1.0 . The compounds ( x = 0.2 – 1.0 ) display the field induced metamagnetic transitions, and the threshold fields first increase and then decrease with an increasing Gd content. The magnetoresistance curves of the Tb0.4Gd0.6Mn6Ge6 compounds in an applied magnetic field up to 50 kOe are presented and the magnetoresistance effects are related to the metamagnetic transitions.