AC and DC resistance behaviour of ZrMo2O8 and HfMo2O8 under high pressure

AC and DC resistance behaviours of HfMo2O8 and ZrMo2O8, synthesized in trigonal phase, were studied up to 5.5 GPa. For ZrMo2O8, slope changes and anomalies were observed in resistance around 0.99 and 2.2GPa. These can he related to already reported phase transitions in ZrMo2O8 from trigonal (α) to monoclinic (δ) and from (δ) to triclinic(ε). In similar measurements carried out on (α)-HfMo2O8, slope changes and anomalies were observed around 1GPa and 1.8 GPa, although the natures of curves were different. This apparently indicates similar types of phase transitions in HfMo2O8, the nature of which could be different from those observed in ZrMo2O8. (author)