Multiple phase transitions and magnetoresistance of HoFe₄Ge₂

Highlights: • Three magnetic transitions at T_N = 51 K, T_f1 = 42 K, and T_f2 = 15 K. • Kinetically arrested phase below a freezing point of ∼11 K. • First-order metamagnetic transition at critical field ∼22 kOe below 35 K. • A large magnetoresistance of ∼30% at a field change of 30 kOe near 15 K. - Abstract: 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 T_N = 51 K, T_f1 = 42 K, and T_f2 = 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 T_f2 (15 K)