Multiple phase transitions and magnetoresistance of HoFe4Ge2

A systematic study of the structural, magnetic, heat capacity, electrical resistivity and magnetoresistance properties of HoFe4Ge2 has been performed. The temperature dependencies of the magnetization and heat capacity show three magnetic transitions at TN = 51 K, Tf1 = 42 K, and Tf2 = 15 K. The high temperature transition is antiferromagnetic ordering and the two low temperature phase transitions are due to rearrangements of the magnetic structure. A kinetically arrested phase is observed below a freezing point of ∼11 K. Below 35 K, the behavior of the isothermal magnetization reflects a first-order metamagnetic phase transition. Multiple phase transitions are also manifested in the electrical resistivity behavior. For a field change of 30 kOe, a large magnetoresistance of ∼30% is observed near Tf2 (15 K).