Effect of Fe substitution on structure and exchange interactions within and between the sublattices of frustrated CoCrO.

Obtaining tunable magnetic states in geometrically frustrated multiferroic compound CoCr2O4 by tuning the sublattice magnetic coupling is indeed of high interest from the fundamental and applied points of view. In this work, Fe substitution effects in Co(Cr1-xFex)2O4 (0 ≤ x ≤0.5) are experimentally investigated through detailed measurements of the crystalline structure and magnetization.

Vortex creep activation energies and depinning currents in CaKFeAsand BaKFeAsrevealed by AC susceptibility measurements.

Systematic ac susceptibility measurements have been carried out to study the vortex dynamics in CaKFeAsand BaKFeAssingle crystals under various temperatures, dc magnetic fields, ac field frequencies and amplitudes. The field-temperature phase diagrams were shown, and the characteristics of irreversibility line were also derived. The specific expressions of activation energy on the parameters of temperature (), current density (), and dc magnetic field () are obtained according to these data.