Close correlation among lattice, spin, and charge in the manganese-based antiperovskite material

The temperature (T)-dependent magnetization, transport, and magnetoresistan ce (MR) properties of a Mn-based compound GaCMn3 that has the antiperovskit e structure were studied using neutron powder diffraction and SQUID measure ments. With decreasing T, the magnetic phase transitions from a paramagneti c to an antiferromagnetic (AFM) state via an intermediate ferromagnetic (FM ) phase are observed in this material. These magnetic transitions and their corresponding resistivity slopes d rho /dT are strongly correlated with li near thermal expansion coefficients of the lattice parameter a(-1) (da/dT). A large negative MR of 50% even at 0.3 T is seen near the phase boundary b etween the FM and AFM states. (C) 2001 Elsevier Science Ltd. All rights res erved.