  Non magnetic insulators/semiconductors with induced magnetism introduced via
transition metal substitution are one of the promising materials in the field
of spintronic, magnetoelectronics and magneto optical devices. In this context,
here, we focus on magnetism induced in a non magnetic insulator CaHfO3, by the
substitution of 4d element Ru, at Hf site. Structural investigations indicate
that substitution of Ru4+ (up to 50%) does not affect the original crystal
structure of the parent compound. Magnetic studies divulge a crossover from a
diamagnetic to paramagnetic state with 20% Ru substitution. Further replacement
of Hf results in a glassy magnetic state in CaHf1-xRuxO3 (0.3 < x < 0.5). The
nature of the low temperature glassiness (below 20 K) in these compositions is
confirmed through Vogel Fulcher and Power law, along with, magnetic memory
effect and relaxation dynamics. The observed glassiness is explained through
the phenomenological hierarchical model. Our studies indicate that the presence
of competing short range interactions among randomly arranged Ru cations in non
magnetic insulator CaHfO3 are responsible for the observed low temperature
magnetic state in this series with compositions > 0.25.
