Glassy magnetic behavior induced by Cu²⁺substitution in the frustrated antiferromagnet ZnCr₂O₄

Abstract

Structure and magnetic properties of the compounds Zn1−xCuxCr2O4 (ZCCO) are investigated systematically. A structural phase transition from space-group symmetry F d3m to I41/amd is observed in ZCCO. The critical value of the doping, x, appears at 0.58 ∼ 0.62 through the appearance of a splitting of diffraction peaks at room temperature. Measurements of dc magnetization, ac susceptibility, memory effect and exchange bias-like (EB-like) effect have been performed to reveal the glassy magnetic behaviors of ZCCO. The system with x 0.50 is suggested as a spin glass-like (SG-like) of magnetic characterization whereas doping values of 0.58 x 0.90 defines the system as a "cluster glass-like" (CG-like) with unidirectional anisotropy. The Cu content suppresses the geometrical frustration of ZnCr2O4, which may correlate with the pinning effect of Cu sublattice on Cr sublattice to a preferential direction.

Effects of Cu Dopant on Lattice and Optical Properties of ZnS Quantum Dots

“…is smaller than that of the Zn 2+ ions (0.74 Å), and so the replacing of Zn 2+ ions with Cu 2+ ions would result in a contraction of the lattice. 22 According to Vegard's law, 23 the relationship between the lattice variation and the dopant concentration should be linear. From Figure 3, we can indeed see that the lattice varies almost linearly with increases in Cu concentration from 0 to 2%.…”

Improving magnetic and structural properties of Zn1–xCuxFeCrO4 by substituting copper synthesized by citrate gel autocombustion route

“…Zn 1À x Cu x FeCrO 4 (where x¼0.0, 0. 25 were used as precursors. The stiochiometric quantity of individual metal nitrates were dissolved in minimum quantity of double distilled and deionised water separately to get a clear, transparent solution.…”

“…In these investigation glassy magnetic behavior was induced due to the substitution of Cu þ 2 ions in the frustrated antiferromagnet ZnCr 2 O 4 [25]. The composition, temperature and frequency dependence of dielectric behavior of zinc substituted copper-ferri-chromates were studied by Chhantbar et al [26].…”

Structural ground states of(A,A′)Cr2O4(A=Mg,Kemei1, Moffitt2, Darago3 et al. 2014Phys. Rev. B30090View full textAdd to dashboardCite

“…When spins are substituted on the non-magnetic A sites of ACr 2 O 4 spinels at concentrations greater than 20%, spin frustration is lifted. [12][13][14] However, at dilute A site spin concentrations, disorder in the spin interactions has been shown to further suppress magnetic ordering. [12][13][14] Due to the disorder in spin interactions, magnetic ordering in Zn 0.9 Co (Table I).…”

“…To understand the degenerate ground states of ACr 2 O 4 spinels, the effect of spin disorder on the magnetic properties of these systems has been investigated; spin disorder is introduced by substituting magnetic ions on the non-magnetic A sublattice of these materials. [12][13][14] Similarly, the effect of low concentrations of magnetic vacancies on the Cr sublattice of ZnCr 2(1−x) Ga 2x O 4 has been studied showing that the freezing temperature of these systems for small x is independent of the spin vacancy concentration. 15 However, the effect of spin and lattice disorder on the structural ground states of the canonical frustrated systems MgCr 2 O 4 and ZnCr 2 O 4 has so far not been studied.Here, we study magnetic ordering and correlated or uncorrelated structual changes in MgCr 2 O 4 and ZnCr 2 O 4 when low concentrations of magnetic cations are substituted on the non-magnetic A site.…”