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In this paper, we report the modulation of structural and magnetic properties with Fe and Cr doping at the Zn and V sites in ZnV2O4. Undoped ZnV2O4 exhibits two anomalies in the M–T measurements which are assigned to a structural transition (TS ~ 57 K) followed by a magnetic transition (TN ~ 41 K). With the help of x-ray diffraction and energy dispersive x-ray analysis it is found that the prepared samples are single phase as well as stoichiometric. However, doping at both the cationic sites of ZnV2O4 leads to the disappearance of the structural transition and suppression of the long range magnetic ordering to a cusp like feature below 20 K and the cusps broaden with increasing magnetic field while the position of the cusps remain unaltered with increasing field strength. The obtained results indicate that Zn1−xFexV2O4 and Zn(V1−tCrt)2O4 (x  =  t  =  0, 0.05, 0.1) systems are frustrated cubic normal spinel systems. Moreover, such field independent behavior of cusp positions hints towards the antiferromagnetic ground state at low temperature instead of a spin glass phase. To elucidate this fact, dc aging (magnetic relaxation) and memory effects have been investigated in zero field cooled (ZFC) and field cooled (FC) protocol for the 10% doped samples, which exhibit aging and memory effect. Our study provides an explicit evidence of spin glass like state instead of low temperature antiferromagnetic ground state in the doped compounds.

We report here, temperature dependent Raman spectroscopic measurements on polycrystalline MnV2O4 over the temperature range of 10–300 K. The main aim of this study is to investigate the spin–phonon correlations across the magnetic and structural transition temperatures in this system. Temperature dependent magnetization measurements combined with the low temperature Raman study show the existence of structural changes in MnV2O4 across the two successive phase transitions. Anomalous changes in line shape parameters in some of the Raman modes are observed during temperature dependent Raman measurements, indicating the presence of spin–phonon coupling. A significantly high spin–phonon coupling strength of 5.9 cm−1 suggests alteration of spin dynamics across magnetic transition temperature, TM (57 K).

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