Magnetism and magnetoresistance studies of HfFe6Ge6-type Y1-xCexMn6Sn6 (x = 0.1-0.3) compounds

Magnetic transitions and the magnetoresistance (MR) effect of the HfFe6Ge6-type Y1-xCexMn6Sn6 (x = 0.1-0.3) compounds have been investigated in the temperature range of 5-385 K. Y0.9Ce0.1Mn6Sn6 and Y0.825Ce0.175Mn6Sn6 show antiferromagnetism and Y0.7Ce0.3Mn6Sn6 undergoes an antiferromagnetic (AFM) to ferrimagnetic (Fi) transition with increasing temperature. The metamagnetic transition from helical antiferromagnetism to ferrimagnetism can be also induced by an applied field for those compounds. The metamagnetic transition field decreases with increasing Ce content, such as from 25 kOe for x = 0.1 to 11 kOe for x = 0.3 at 5 K. The giant MR (GMR) effect for Y1-xCexMn6Sn6 (x = 0.1-0.3) is observed with metamagnetic behaviour, such as -37% at 5 K under a field of 50 kOe for the compounds (x = 0.175 and 0.3). It is found that the MR behaviour for Y0.7Ce0.3Mn6Sn6 in the Fi state follows the magnetic-field power law MR ∼ - Hq at a fixed temperature, and obeys the relationship MR = -[α + β/(T + γ] under a fixed magnetic field