Effect of Ho substitution on structure and magnetic properties of BiFeO3

Structure and magnetic properties of trivalent Ho substituted BiFeO3 (HoxBi1-xFeO3) have been studied for the compositional range x = 0 to 0.2. The structure remains in rhombohedral R3c for x < 0.15, and further increase in x results a structural transition to orthorhombic Pnma. The decrease in Raman modes and the appearance of new mode at 475 cm(-1) confirms the structural changes. Ho doping at Bi site breaks the spin cycloid of BiFO3 and leads to the observation of ferromagnetic order at low temperatures. With increase in temperature, the M-H curves exhibit a pinching leading to double hysteresis loops. A minimum is observed in M-T curves for low fields at compensation temperature (Theta(C)) and H-C attains a maximum close to Theta(C). Variation of H-C with temperature is discussed in terms of a model consisting of two sublattices. The improved magnetic properties achieved by Ho doping enhance the potential of BiFeO3 for multiferroic applications. (C) 2014 AIP Publishing LLC.