Magnetic phase diagrams in the H-T plane of the magnetically strongest sigma-phase Fe-V compounds

TL;DR

This study maps the magnetic phase diagrams of Fe-V sigma-phase compounds, revealing a re-entrant magnetic behavior with complex spin glass states and critical lines influenced by magnetic fields.

Contribution

It provides the first detailed magnetic phase diagrams of Fe-V sigma-phase compounds, highlighting the re-entrant magnetism and the crossover of critical lines within the spin glass state.

Findings

Re-entrant magnetic phase diagrams in H-T plane.

Identification of two sub-phases within the spin glass state.

Crossover from Gabay-Toulouse to Almeida-Touless behavior.

Abstract

Magnetization measurements were performed on two sigma-phase samples of Fe(100-x)V(x) (x=35.5, 34.1) vs. temperature, T, and in DC magnetic field, of various amplitudes. Using three characteristic temperatures, magnetic phase diagrams in the H-T plane have been designed testifying to a re-entrant character of magnetism. The ground magnetic state, a spin glass (SG), was evidenced to be composed of two sub phases: one with a weak irreversibility and the other with a strong irreversibility. Two critical lines were reconstructed within the SG state. Both of them show a crossover from the Gabay-Toulouse behavior (low field) to a linear and/or quasi-Almeida-Touless behavior. A strong difference in the effect of the applied magnetic field on the SG phase in the two samples was revealed.