Structural and magnetic properties of LaVO3 - Absence of anomalous diamagnetism

Abstract

The novel magnetic and structural properties of LaVO3 have been studied in a comprehensive manner using X-ray and neutron powder diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, electrical transport, and dc magnetization. The lattice parameters have been found to be larger than previously reported, indicating the possibility of a novel phase. For vanadium ions, the valence state is found to be in accordance with the expected value (+3), the effect of larger lattice parameters is also present in the X-ray absorption spectroscopy measurement. Magnetic transition due to the antiferromagnetic ordering of the vanadium sublattice is observed at 142 K (TN). It undergoes a transition to a monoclinic crystal structure below 140 K (Tt). Negative magnetization (anomalous diamagnetism), which has been reported in earlier studies on the magnetic properties of LaVO3, is not observed in the present study. In the M − H isotherms, the ferromagnetic component of vanadium spins is absent. Below TN, the estimated magnetic structure of vanadium sublattice from powder neutron diffraction measurements is C-type antiferromagnetic, which persists in the entire low temperature region. The observed novel structural phase gives rise to pure C-type antiferromagnetic arrangement without weak ferromagnetic component. Theoretical calculations have been carried out to understand the nature of the magnetic ground state.